Search results for: dye degradation/removal

Authors: Marzieh Joda, Narges Fallah, Neda Afsham

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Graphite-supported two different of morphology α and β -Ni (OH)₂ electrodes were prepared by electrochemical deposition at appropriate potentials with regard to Ni (II)/Ni (III) redox couple under alkaline and acidic conditions, respectively, for selective oxidation of ammonia to nitrogen in the direct electro-oxidation process. Cyclic voltammetry (CV) of the electrolyte containing NH₃ indicated mediation of electron transfer by Ni (OH)₂ and the electrode surface was analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectrometer (RS), and X-ray photoelectron spectroscopy (XPS). Results of surface characterization indicated the presence of α polymorphs which is the stable phase of Ni (OH)₂ /Graphite. Cyclic voltammograms gave information on the nature of electron transfer between nitrogen species and working electrode and revealed that the potential has depended on both nature ammonia oxidation and that of concentration. The mechanism of selective ammonia conversion to nitrogen and byproducts, namely NO₂- and NO₃- was established by Cyclic voltammograms and current efficiency. The removal efficiency and selective conversion of ammonia (0.1 M KNO₃ + 0.01 M Ni(NO₃)₂, pH 11, 250°C) on Nickel Oxide-hydroxide /Graphite was determined based on potential controlled experiments.

Keywords: Electro deposition, Nickel oxide-hydroxide, Nitrogen selectivity, Ammonia oxidation

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Authors: N. Ouslimani, M. T. Abadlia

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Environment protection is a precondition for sustained growth and a better quality of life for all people on earth. Aqueous industrial effluents are the main sources of pollution. Among the compounds of these effluents, dyes are particularly resistant to discoloration by conventional methods, and discharges present many problems that must be supported. The scientific literature shows that synthetic organic dyes are compounds used in many industrial sectors. They are found in the chemical, car, paper industry and particularly the textile industry, where all the lines and grades of the chemical family are represented. The affinity between the fibers and dyes vary depending on the chemical structure of dyes and the type of materials to which they are applied. It is not uncommon to find that during the dyeing operation from 15 to 20 % of sulfur dyes, and sometimes up to 40 % of the reactants are discharged with the effluent. This study was conducted for the purpose of fading basics dyes from wastewater using as adsorbent fiber waste material. This technique presents an interesting alternative to usual treatment, as it allows the recovery of waste fibers, which can find uses as raw material for the manufacture of cleaning products or in other sectors In this study the results obtained by fading fiber waste are encouraging, given the rate of color removal which is about 90%.This method also helps to decrease BOD and suspended solids MES in an effective way.

Keywords: adsorption, dyes, fiber, valorization, wastewater

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Authors: Hashem Barati, Afshin Farahbakhsh

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The flowers of saffron contain anthocyanins. Generally, extraction of anthocyanins takes place at low temperatures (below 30 °C), preferably under vacuum (to minimize degradation) and in an acidic environment. In order to extract anthocyanins, the dried petals were added to 30 ml of acidic ethanol (pH=2). Amount of petals, extraction time, temperature, and ethanol percentage which were selected. Total anthocyanin content was a function of both variables of ethanol percent and extraction time.To prepare SW with pH of 3.5, different concentrations of 100, 400, 700, 1,000, and 2,000 ppm of sodium metabisulfite were added to aqueous sodium citrate. At this selected concentration, different extraction times of 20, 40, 60, 120, 180 min were tested to determine the optimum extraction time. When the extraction time was extended from 20 to 60 min, the total recovered anthocyanins of sulfur method changed from 650 to 710 mg/100 g. In the EW method Cellubrix and Pectinex enzymes were added separately to the buffer solution at different concentrations of 1%, 2.5%, 5%, 7%, 10%, and 12.5% and held for 2 hours reaction time at an ambient temperature of 40 °C. There was a considerable and significant difference in trends of Acys content of tepals extracted by pectinex enzymes at 5% concentration and AE solution.

Keywords: saffron, anthocyanins, acidic environment, acidic ethanol, pectinex enzymes, Cellubrix enzymes, sodium metabisulfite

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Authors: U. P. L. Wijayarathne, P. W. Vidanage, H. K. D. Jayampath, K. W. P. M. Kothalawala

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Feasibility of utilizing Empty Bunch (EB) fibre, a solid waste of palm oil extraction process, as an adsorbent is analysed in this study. Empty bunch fibre is generated after the extraction of retained oil in the sterilized and threshed empty fruit bunches. Besides the numerous characteristics of EB fibre, which enable its utilization as a fuel, a bio-composite material, or mulch, EB fibre also shows exceptional characteristics of a good adsorbent. Fixed bed adsorption method is used to study the adsorptivity of EB fibre using a continuous adsorption column with Methyl-blue (1.13ppm) as the feed. Adsorptivity is assumed to be solely dependent on the bed porosity keeping other parameters (feed flow rate, bed height, bed diameter, and operating temperature) constant. Bed porosity is changed by means of compact ratio and the variation of the feed concentration is analysed using a photometric method. Break through curves are plotted at different porosity levels and optimum bed porosity is identified for a given feed stream. Feasibility of using the EB fibre as an inexpensive and an abundant adsorbent in wastewater treatment facilities, where the effluent colour reduction is adamant, is also discussed.

Keywords: adsorption, fixed bed, break through time, methylene blue, oil palm fibre

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Authors: Mansoor Imam, Amber Afshan, Sumbul Mujeeb, Kamran Gill

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An investigative approach has been made to study the quality of living prevailing in the squatter slums of Karachi city that is influencing the urbanization trends and environmental degeneration of built environment. The paper identifies the issues and aspects that have directly and indirectly impacted the degeneration owing to inadequate basic infrastructural amenities, substandard housing, overcrowding, poor ventilation in homes and workplaces, and noncompliance with building bye-laws and regulations, etc. Primarily, secondary data has been critically examined and analyzed which was however not limited to census data, demographic / socioeconomic data, official documents and other relevant secondary data were obtained from existing literature and GIS. It is observed that the poor and sub-standard housing / living quality have serious adverse impacts on the environment and the health of city residents. Hence strategies for improving the quality of built environment for sustainable living are mandated. It is, therefore, imperative to check and prevent further degradation and promote harmonious living and sustainable urbanization.

Keywords: squatter slums, urbanization, degenerations, living quality, built environment

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Authors: Eke Bala Sophie Michelle

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The renewable resource character of NTFPs is an opportunity to its sustainability, this study analyzed the role of social capital in the adoption of sustainable management practices of NTFPs by households in the community forest (CF) Morikouali-ye. The analysis shows that 67% of households surveyed perceive the level of degradation of NTFPs in their CF as time passes and are close to 74% for adoption of sustainable management practices of NTFPs that are domestication, sustainable management of the CF, the logging ban trees and uprooting plants, etc. 26% refused to adopt these practices estimate that, at 39% it is better to promote logging in the CF. The estimated probit model shows that social capital through trust, solidarity and social inclusion significantly influences the probability of households to adopt sustainable NTFP management practices. In addition, age, education level and income from the sale of NTFPs have a significant impact on the probability of adoption. The probability of adoption increases with the level of education and confidence among households. So should they be animated by a spirit of solidarity and trust and not let a game of competition for sustainable management of NTFPs in their CF.

Keywords: community forest, social capital, NTFP, trust, solidarity, social inclusion, sustainable management

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Authors: Merle Bischoff, Thomas Gries, Gunnar Seide

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Pesticides, which harm crop enemies, but can also interfere with the human body, are nowadays mostly used for crop spraying. Silica particles (SiO2) in the nanometer and micrometer scale offer a physical way to combat insects without harming humans and other mammals. Thereby, they allow foregoing pesticides, which can harm the environment. As silica particles are supplied as a powder or in a suspension to farmers, the silica use in large scale agriculture is not sufficient due to erosion through wind and rain. When silica is implemented in a textile’s surface (nanocompound), particles are locally bound and do resist erosion, but can function against bugs. By choosing polypropylene as a matrix polymer, the production of an inexpensive agritextile with an 'anti-bug' effect is made possible. In the Symposium the results of the manufacturing and filament spinning of silica nanocomposites from a polypropylene basis is compared to the fabrication from nanocomposites based on Polybutylene succinate, a biodegradable composite. The investigation focuses on the difference between degradable nanocomposite and stable nanocomposite. Focus will be laid on the filament characteristics as well as the degradation of the nanocompound to underline their potential use and application as an agricultural textile.

Keywords: agriculture, environment, insects, protection, silica, textile, nanocomposite

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Authors: Teodrose Atnafu Abegaze, P. K. Sharma

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In this study, an attempt has been made to study the behavior of breakthrough curves in both layered and mixed heterogeneous soil by conducting experiments in long soil columns. Sodium chloride has been used as a conservative tracer in the experiment. Advective dispersive transport equations, including equilibrium sorption and first-order degradation coefficients, are used for solute transport through mobile-immobile porous media. In order to do the governing equation for solute transport, there are explicit and implicit schemes for our condition; we use an implicit scheme to numerically model the solute concentration. Results of experimental breakthrough curves indicate that the behavior of observed breakthrough curves is approximately similar in both cases of layered and mixed soil, while earlier arrival of solute concentration is obtained in the case of mixed soil. It means that the types of heterogeneity of the soil media affect the behavior of solute concentration. Finally, it is also shown that the asymptotic dispersion model simulates the experimental data better than the constant and linear distance-dependent dispersion models.

Keywords: numerical method, distance dependant dispersion, reactive transport, experiment

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Authors: S. Abdulsalam, A. D. I. Suleiman, N. M. Musa, M. Yusuf

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Environment free of pollutants should be the concern of every individual but with industrialization and urbanization it is difficult to achieve. In view of achieving a pollution limited environment at low cost, a study was conducted on the use of bioremediation technology to remediate hydrocarbons and three heavy metals namely; copper (Cu), zinc (Zn) and iron (Fe) from a typical petroleum refinery wastewater in a closed system. Physicochemical and microbiological characteristics on the wastewater sample revealed that it was polluted with the aforementioned pollutants. Isolation and identification of microorganisms present in the wastewater sample revealed the presence of Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus and Staphylococcus epidermidis. Bioremediation experiments carried out on five batch reactors with different compositions but at same environmental conditions revealed that treatment T5 (boosted with the association of Bacillus subtilis, Micrococcus luteus) gave the best result in terms of oil and grease content removal (i.e. 67% in 63 days). In addition, these microorganisms were able of reducing the concentrations of heavy metals in the sample. Treatments T5, T3 (boosted with Bacillus subtilis only) and T4 (boosted with Micrococcus luteus only) gave optimum percentage uptakes of 65, 75 and 25 for Cu, Zn and Fe respectively.

Keywords: boosted, bioremediation, closed system, aeration, uptake, wastewater

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Authors: Fakhr Eddin Alnaal, Angela Dahdal, Duaa Aladib, Sabeen Ibrahim, Ibrahim Ghoraibi, Bissan Ahmed

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Dementia is one of the diseases which had several stages and Alzheimer’s term was selected in respect for the first doctor Alzheimer who defined the first symptoms of this diseases in a woman whom was well treated by him. The fact that this is a type of a silent disease on which you have a long-term process of neurological degradation and suddenly gives symptoms which are most often irreversible, on clinical level likely we can consider it as a malignancy, one in terms of that it is sudden shocking irreversible and on the level of behavior and some mortality beside the lack of early detection tools for diagnosis. Therefore, the goal of our project is to test the concept of the ability of Statin in prevention of such disease and we investigated that both on experimental level and most importantly on clinical one, the clinical part was performed in a recognized house of aged people who had accidently a high cholesterol and were for years given Statin to treat that elevation, however after the symptoms of Alzheimer’s appeared and when diagnosed, they were well treated and rapidly recovered compared to Alzheimer’s patients in the same house who did not receive Statin had a mild improvement in their symptoms after the therapy, on the other hand we confirmed such observation by a well-organized experimental work.

Keywords: Alzheimer's, dementia, silent disease, statin

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Authors: Rataya Yanaphan, Saksiri Kuppatarat, Sarita Pinmanee

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Hemp (Cannabis sativa L. ssp. Sativa) cultivation for fiber is limited by extremely high labor cost, especially for the removal of the leaves before harvest. This study evaluated chemical defoliants as a means to remove the leaves of hemp before harvest, in an effort to reduce labor expenditures in the production on hemp fiber. This study was conducted by spraying the leaves of hemp with five different treatments: saline solution, Urea (CH4N2O), Ethephon, copper Sulphate (CuSO4) and water (control) before harvesting. The largest percentage of leaf loss 6 days after spraying was with saline solution (43%), followed by Ethephon (32%). However, saline solution also caused drying of the stems but Ethephon did not. Thus, Ethephon was evaluated in the second experiment by spraying with Ethephon concentrations of 0, 10, 15 and 20 ml per 1 liter of water at 7 days before harvest. Spraying with 0.5% Ethephon resulted in 13.6% leaf fall. Spraying with 1.5% and 2% Ethephon resulted in 82.2% and 82.3 % leaf fall, respectively. In addition, using Ethephon to defoliate hemp had no detrimental effect the yield. Therefore, Ethephon concentration at 15 ml per 1 liter of water will be recommended for use in removing hemp leaves by spraying at 7 days before harvest to lower labor cost.

Keywords: defoliation technology, ethephon, hemp cultivation, saline solution

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Authors: Michelle Zeyuan Ma, Hermann Heilmeier

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Recently, meat production ecosystem impacts initiated many hot discussions and researchers, and it is a difficult implementation to reduce such impacts due to the demand of meat products. It calls for better management and control of ecosystem impacts from every aspects of meat production. This article analyzes the ecosystem impacts of meat production based on meat products life cycle. The analysis shows that considerable ecosystem impacts are caused by different meat production steps: initial establishment phase, animal raising, slaughterhouse processing, meat consumption, and wastes management. Based on this analysis, the impacts are summarized as: leading factor for biodiversity loss; water waste, land use waste and land degradation; greenhouse gases emissions; pollution to air, water, and soil; related major diseases. The article also provides a discussion on a solution-sustainable food system, which could help in reducing ecosystem impacts. The analysis method is based on the life cycle level, it provides a concept of the whole meat industry ecosystem impacts, and the analysis result could be useful to manage or control meat production ecosystem impacts from investor, producer and consumer sides.

Keywords: eutrophication, life cycle based analysis, sustainable food, waste management

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Authors: Akanimo Emene, Mark D. Ogden, Robert Edyvean

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Adsorption is a low cost, efficient and economically viable wastewater treatment process. Utilization of this treatment process has not been fully applied due to the complex and not fully understood nature of the adsorption system. To optimize its process is to choose a sufficient adsorbent and to study further the experimental parameters that influence the adsorption design system. Chemically modified adsorbent, Luffa cylindrica, was used to adsorb heavy metal ions and an organic pollutant, methylene blue, from aqueous environmental solution at varying experimental conditions. Experimental factors, adsorption time, initial metal ion or organic pollutant concentration, ionic strength, and pH of solution were studied. The experimental data were analyzed with kinetic and isotherm models. The antagonistic effect of the methylene and some heavy metal ions were recorded. An understanding of the use of this treated Luffa cylindrica for the removal of these toxic substances will establish and improve the commercial application of the adsorption process in treatment of contaminated waters.

Keywords: adsorption, heavy metal ions, Luffa cylindrica, wastewater treatment

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Authors: A. H. Jagaba, Musa Babayo, Ab Aziz Abdul Latiff, Sule Abubakar, I. M. Lawal, Isa Zubairu, M. A. Nasara

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Wastewater containing heavy metals is of extreme importance globally because of its potential threat to both the aquatic ecosystem and the soil environment. Heavy metal is hazardous even at low concentration and thereby causing various forms of diseases. One method which has been tested and found to be effective for heavy metals removal is coagulation-flocculation. For the coagulation process of POME obtained from Pertubuhan Peladang Negeri Johor (PPNJ), Oil Palm Mill Company located in Kahang area of Kluang, Johor Darul Takzim, Malaysia, diffèrent coagulants would be used to absorb and then separate the metals from wastewater. The determination of heavy metals concentration in POME was carried out using an inductively coupled plasma (ICP) and an Atomic Absorption Spectrometer (AAS). Results of the study showed that alum coagulant was successful in effectively reducing Cu, Cd, and Mn from 0.840 mg/l, 0.00509 mg/l and 8.191 mg/l to as low as 0.107 mg/l, 0.000270 mg/l and 0.612 mg/l respectively. All were obtained at a dose of 1000 mg/l. 1000 mg/l dose of ferric chloride reduced Pb concentration from 0.0248 mg/l to 0.00151 mg/l. Chitosan was best at reducing Fe and Zn from 62.91 mg/l and 3.616 mg/l to 6.003 mg/l and 0.595 mg/l all at a dose of 400 mg/l.

Keywords: palm oil mill effluent, coagulation, heavy metals, Pertubuhan Peladang Negeri Johor, Malaysia

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Authors: A. Altomi, A. Alhebshi, M. Rasm, B. Osman

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This study explored the application of chitin nanocrystals (ChiNCs), derived from a renewable and environmentally friendly material, as stabilizers for oil-in-water (O/W) emulsions. O/W emulsions are commonly used in various applications but are prone to instability and degradation over time. Instability can occur due to factors such as flocculation, coalescence, and gravitational separation, including creaming and sedimentation, either independently or simultaneously. To produce ChiNCs, chitin powder underwent acid hydrolysis. Transmission electron microscopy (TEM) analysis revealed that ChiNCs exhibited a needle-like morphology, with lengths ranging from 200 to 800 nm and widths ranging from 20 to 80 nm. The surface charge of ChiNCs was negative at pH values above 7 and positive at pH values below 7. The rheological properties of O/W emulsions stabilized by ChiNCs were compared to those stabilized by synthetic surfactants, namely Tween 80 and CTAB. The emulsions stabilized by ChiNCs demonstrated higher yield stress and lower shear viscosity compared to those stabilized by synthetic surfactants. This indicates that ChiNC-stabilized emulsions are more stable and less prone to breakdown. Based on these findings, ChiNCs show promise as an alternative to synthetic surfactants for stabilizing O/W emulsions.

Keywords: chitin nanocrystals, colloidal pickering, emulsion rheology, oil-in-water, synthetic surfactant

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Authors: Benedict Okundaye, Patricia Tzortzopoulos, Yun Gao

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Scholars and international organisations have contended that developing nations lack the technical expertise, infrastructure, and ability to cope with or prepare for the neighbourhood’s sustainable development as Sustainable Development Goals, mainly targeting goal 11 unimpressive accomplishments. Both wealthy and impoverished communities are facing increasing issues due to rapid urbanisation and pandemics, particularly in Africa. The global neighbourhood challenges, especially in developing countries such as South Africa, include pollution poverty, energy poverty, digital poverty, environmental degradation, social exclusion, and socioeconomic inequalities. With the problematic international sustainability assessment tools lingering, few researchers have produced frameworks to engage the local contexts, but improvements are still required. This research anchors on developing a people-centred, flexible, and adaptable neighbourhood sustainability assessment framework that becomes a tool to assess the characteristics of neighbourhood sustainability in South Africa. The conceptual framework employs a variety of approaches, including broader dimensional factors, a closed-ended questionnaire, and statistical analysis to improve on and complement other existing frameworks.

Keywords: participation, development, inclusion, urbanism, cities, resilience

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Authors: Christine Odinga, Fred Otieno, Josiah Adeyemo

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A study was done to establish the effectiveness of wetland plants: Echinocloa pyramidalis (L) and Cyperus papyrus (L) in purifying wastewater from sugar factory stabilization pond effluent. A pilot-scale Free Water Surface Wetland (FWSCW) system was constructed in Chemelil sugar factory, Kenya for the study. The wetland was divided into 8 sections (cells) and planted with C. papyrus and E. pyramidalis in alternating sequence. Water samples and plant specimen were taken fortnightly at inlets and outlets of the cells and analysed for total phosphates and total nitrates. The data was analysed by use of Microsoft excel and SPSS computer packages. Water analysis recorded a reduction in the nutrient levels between the inlet pond nine and the final outlet channel to River Nyando. The plants grown in the wetland experienced varied increases and reductions in the level of total foliar nitrogen and phosphorous, indicating that though the nutrients were being removed from the wetland, the same were not those assimilated by the plants either. The control plants had higher folia phosphorous and nitrogen, an indication that the system of the constructed wetland was able to eliminate the nutrients effectively from the plants.

Keywords: wetlands, constructed, plants, nutrients, wastewater, industrial

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Authors: Amina Adala, Nadra Debbache, Tahar Sehili

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Coordination polymers and uniformly {[Zn(II)(BIPY)(Pht)]n} (1), {[Zn (HYD)(Pht)]n} (2) (BIPY = 4,4’ bipyridine, Pht = terephtalic acid, HYD = 8-hydroxyquinoline) have been successfully synthesized by a hydrothermal process using aqueous zinc solution. The as-prepared compounds phases were characterized by X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy, UV-visible spectroscopy, thermogravimetric analysis (TGA), and the electrochemistry study by the voltammetry cyclic. The results showed a crystalline phase for CP1 however, CP2 requires recrystallization; the FTIR showed the presence of characteristic bands of all ligands; besides that, TGA shows thermal stability up to 300°C. The electrochemistry study showed a good charge transfer between the ligands and Zn metal for the two components. UV-Vis measurement showed strong absorption in a wide range from UV to visible light with a band gap of 2.69 eV for CP1 and 2.56 eV for CP2, smaller than that of ZnO. This represents an alternative to using ZnO. The Ibuprofen IBP decomposition kinetics of 5.10⁻⁵ mol.L⁻¹ under solar and artificial light were studied for different irradiation conditions. Good photocatalytic properties were observed due to their high surface area.

Keywords: metal-organic frameworks, photocatalysis, photodegradation, organic pollutant, ibuprofen

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Authors: R. Karmouch

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A thin gold metal layer was deposited on the top of silicon oxide films containing embedded Si nanocrystals (Si-nc). The sample was annealed in gas containing nitrogen, and subsequently characterized by photoluminescence. We obtained 3-fold enhancement of photon emission from the Si-nc embedded in silicon dioxide covered with a Gold layer as compared with an uncovered sample. We attribute this enhancement to the increase of the spontaneous emission rate caused by the coupling of the Si-nc emitters with the surface plasmons (SP). The evolution of PL emission with laser irradiated time was also collected from covered samples, and compared to that from uncovered samples. In an uncovered sample, the PL intensity decreases with time, approximately with two decay constants. Although the decrease of the initial PL intensity associated with the increase of sample temperature under CW pumping is still observed in samples covered with a gold layer, this film significantly contributes to reduce the permanent deterioration of the PL intensity. The resistance to degradation of light-emitting silicon nanocrystals can be increased by SP coupling to suppress the permanent deterioration. Controlling the permanent photodeterioration can allow to perform a reliable optical gain measurement.

Keywords: photodeterioration, silicon nanocrystals, ion implantation, photoluminescence, surface plasmons

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Authors: Mabtho Moreroa-Monyelo, Grace Ijoma, Rosina Nkuna, Tonderayi Matambo

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A moving bed biofilm reactor (MBBR) was used for the bioremediation of high strength chemical oxygen demand (COD) Fisher-Tropsch (FT) wastewater. The aerobic MBBR system was operated over 60 days. For metagenomics profile assessment of the targeted 16S sequence of bacteria involved in the bioremediation of the chemical compounds, sludge samples were collected every second day of operation. Parameters such as pH and COD were measured daily to compare the system efficiency as the changedin microbial diversity progressed. The study revealed that pH was a contributing factor to microbial diversity, which further affected the efficiency of the MBBR system. The highest COD removal rate of 86.4% was achieved at pH 8.3. It was observed that when there was more, A higher bacterial diversity led to an improvement in the reduction of COD. Furthermore, an OTUof 4530 was obtained, which were divided into 12 phyla, 27 classes, 44 orders, 74 families, and 138 genera across all sludge samples from the MBBR. A determination of the relative abundance of microorganisms at phyla level indicates that the most abundant phylum on day it was Firmicutes (50%); thereafter, the most abundant phylum changed toProteobacteria.

Keywords: biodegradation, fischer-tropsch wastewater, metagenomics, moving bed biofilm reactor

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Authors: Raquel Bayon, Ainara Lopez-Ortega, Elena Rodriguez, Amaya Igartua

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Corrosion is one of the most concerning phenomenon that accelerates material degradation in offshore applications. In order to avoid the premature failure of metallic materials in marine environments, organic coatings have widely been used, due to their elevated corrosion resistance. Thermally-sprayed metals have recently been used in offshore applications, whereas ceramic materials are usually less employed, due to their high cost. The protectiveness of the coatings can be evaluated and categorized in corrosivity categories in accordance with the ISO 12944-6 Standard. According to this standard, for coatings that are supposed to work in marine environments, a C5-M category is required for components working out of the water or partially immersed in the splash zone, and an Im2 category for totally immersed components. C5-M/Im-2 high category would correspond to a durability of more than 20 years without maintenance in accordance with ISO 12944 and NORSOK M501 standards. In this work, the corrosion behavior of three potential coatings used in offshore applications has been evaluated. For this aim, the materials have been subjected to different environmental conditions in several climatic chambers (humidostatic, climatic, immersion, UV and salt-fog). The category of the coatings to each condition has been selected, in accordance with the previously mentioned standard.

Keywords: cabinet, coatings, corrosion, offshore

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Authors: Seyed-Ahmad Shahidi, Salemeh Kazemzadeh, Mehdi Sharifi Soltani, Azade Ghorbani-HasanSaraei

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The kinetics of colour changes of American Pokeweed extract, due to concentration by various heating methods was studied. Three different heating/evaporation processes were employed for production of American Pokeweed extract concentrate. The American Pokeweed extract was concentrated to a final 40 °Brix from an initial °Brix of 4 by microwave heating, rotary vacuum evaporator and evaporating at atmospheric pressure. The final American Pokeweed extract concentration of 40 °Brix was achieved in 188, 216 and 320 min by using microwave, rotary vacuum and atmospheric heating processes, respectively. The colour change during concentration processes was investigated. Total colour differences, Hunter L, a and b parameters were used to estimate the extent of colour loss. All Hunter colour parameters decreased with time. The zero-order, first-order and a combined kinetics model were applied to the changes in colour parameters. All models were found to describe the L, a and b-data adequately. Results indicated that variation in TCD followed both first-order and combined kinetics models. This model implied that the colour formation and pigment destruction occurred during concentration processes of American Pokeweed extract.

Keywords: American pokeweed, colour, concentration, kinetics

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Authors: Ankur Gupta, Jayant Raj Saurav, Shantanu Bhattacharya

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In this work we report an effective water filtration system based on the photo catalytic performance of semiconducting dense nano-brushes under natural sunlight. During thin-film photocatalysis usually performed by a deposited layer of photocatalyst, a stagnant boundary layer is created near the catalyst which adversely affects the rate of adsorption because of diffusional restrictions. One strategy that may be used is to disrupt this laminar boundary layer by creating a super dense nanostructure near the surface of the catalyst. Further it is adequate to fabricate a structured filter element for a through pass of the water with as grown nanostructures coming out of the surface of such an element. So, the dye remediation is performed through solar means. This remediation was initially limited to lower efficiency because of diffusional restrictions but has now turned around as a fast process owing to the development of the filter materials with standing out dense nanostructures. The effect of increased surface area due to microholes on fraction adsorbed is also investigated and found that there is an optimum value of hole diameter for maximum adsorption.

Keywords: nano materials, photocatalysis, waste water treatment, water remediation

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Authors: Jorge Santos, Ana V. Girão, F. J. Oliveira, Alexandre C. Bastos

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Protective or decorative coatings containing hexavalent chromium compounds are still used on metal and plastic parts. These hexavalent chromium compounds represent a risk to living beings and the environment, and, for this reason, there is a great need to investigate alternatives. Physical Vapor Deposition (PVD) is an environmentally friendly process that allows the deposition of wear and corrosion resistant thin films with excellent optical properties. However, PVD thin films are porous and if deposited onto low corrosion resistant substrates, lead to a degradation risk. The corrosion behavior of chromium-free electroplated coating systems finished with magnetron sputtered PVD thin films was investigated in this work. The electroplated systems consisted of distinct nickel layers deposited on top of a copper interlayer on acrylonitrile butadiene styrene (ABS) plates. Electrochemical and corrosion evaluation was conducted by electrochemical impedance spectroscopy and polarization curves on the different electroplated coating systems, with and without PVD thin film on top. The results show that the corrosion resistance is lower for the electroplated coating systems finished with PVD thin film for extended exposure periods when compared to those without the PVD overlay.

Keywords: PVD, electroplating, corrosion, thin film

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Authors: Ainara Lopez-Ortega, Raquel Bayon, Elena Rodriguez, Amaya Igartua

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The materials used in offshore structural applications are continuously subjected to aggressive environmental conditions that accelerate their degradation, thus shortening their useful life. Wear, corrosion and the effect of marine microorganisms are the main processes taking place in marine environments, and whenever they occur simultaneously the durability of materials is strongly reduced. In the present work, the tribocorrosion behaviour of a High-Strength Low-Alloy (HSLA) steel and three coatings commonly used for protecting offshore components has been studied by means of unidirectional tribological tests in synthetic seawater. The coatings were found to enhance the tribological response of the uncoated steel and provide the system with improved corrosion resistance, in terms of smaller material losses and reduction of friction coefficients. The tests were repeated after ageing the materials in a salt-fog cabinet, and the aging process was found to slightly affect the performance of two of the coatings, in terms of higher material losses, meanwhile the third coating was not affected.

Keywords: coatings, corrosion, high-strength low-alloy steel, seawater, tribocorrosion

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Authors: Mahdi Rahaie

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MicroRNAs are a novel class of small RNAs which regulate gene expression by translational repression or degradation of messenger RNAs. To produce sensitive, simple and cost-effective assays for microRNAs, detection is in urgent demand due to important role of these biomolecules in progression of human disease such as Alzheimer’s, Multiple sclerosis, and some other neurodegenerative diseases. Herein, we report several novel, sensitive and specific microRNA nanobiosensors which were designed based on colorimetric and fluorescence detection of nanoparticles and hybridization chain reaction amplification as an enzyme-free amplification. These new strategies eliminate the need for enzymatic reactions, chemical changes, separation processes and sophisticated equipment whereas less limit of detection with most specify are acceptable. The important features of these methods are high sensitivity and specificity to differentiate between perfectly matched, mismatched and non-complementary target microRNAs and also decent response in the real sample analysis with blood plasma. These nanobiosensors can clinically be used not only for the early detection of neuro diseases but also for every sickness related to miRNAs by direct detection of the plasma microRNAs in real clinical samples, without a need for sample preparation, RNA extraction and/or amplification.

Keywords: hybridization chain reaction, microRNA, nanobiosensor, neurodegenerative diseases

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Authors: Jiangyong Liu, Xiangxiang Xu, Bote Luo, Xiaoxue Luo, Jiang Zhu, Lingzhi Yi

Abstract:

To address the problems of non-linearity and high randomness of the original power load sequence causing the degradation of power load forecasting accuracy, a short-term load forecasting method is proposed. The method is based on the Least Square Support Vector Machine optimized by an Improved Sparrow Search Algorithm combined with the Variational Mode Decomposition proposed in this paper. The application of the variational mode decomposition technique decomposes the raw power load data into a series of Intrinsic Mode Functions components, which can reduce the complexity and instability of the raw data while overcoming modal confounding; the proposed improved sparrow search algorithm can solve the problem of difficult selection of learning parameters in the least Square Support Vector Machine. Finally, through comparison experiments, the results show that the method can effectively improve prediction accuracy.

Keywords: load forecasting, variational mode decomposition, improved sparrow search algorithm, least square support vector machine

Procedia PDF Downloads 93

Authors: Boonsiri Dandumrongsin, Halis Simsek, Chaiwat Rongsayamanont

Abstract:

Dissolved organic nitrogen (DON) is known as one of the persistence nitrogenous pollutant being originated from secondary treated effluent of municipal sewage treatment plant. However, effect of key system operating condition on the fate and behavior of residual DON in the treated effluent is still not known. This study aims to investigate effect of organic loading rate (OLR) on the residual level of DON in the biofilm reactor effluent. Synthetic municipal wastewater was fed into moving bed biofilm reactors at OLR of 1.6x10-3 and 3.2x10-3 kg SCOD/m3-d. The results showed higher organic removal efficiency was found in the reactor operating at higher OLR. However, DON was observed at higher value in the effluent of the higher OLR reactor than that of the lower OLR reactor evidencing a clear influence of OLR on the residual DON level in the treated effluent of the biofilm reactors. It is possible that the lower DON being observed in the reactor at lower OLR is likely to be a result of providing the microbe with the additional period for utilizing the refractory DON molecules during operation at lower organic loading. All the experiments were repeated using raw wastewaters and similar trend was obtained.

Keywords: dissolved organic nitrogen, hydraulic retention time, moving bed biofilm reactor, soluble microbial products

Procedia PDF Downloads 272

Authors: Ntungamili Kenosi, Moatlhodi W. Letshwenyo

Abstract:

Negative environmental impacts due to construction of large projects such as dams have become an important aspect of land degradation. This paper will review the previous literature on the previous researches or study in the same area of study in the other parts of the world. After dam has been constructed, the actual environmental impacts are investigated and compared to the predicted results of the carried out Environmental Impact Assessment. GIS and Remote Sensing, play an important role in generating automated spatial data sets and in establishing spatial relationships. Results from other sources shows that the normalized vegetation index (NDVI) analysis was used to detect the spatial and temporal change of vegetation biomass in the study area. The result indicated that the natural vegetation biomass is declining. This is mainly due to the expansion of agricultural land and escalating human made structures in the area. Urgent environmental conservation is necessary when adjoining projects site. Less study on the evaluation of EIA on dam has been conducted in Botswana hence there is a need for the same study to be conducted and then it will be easy to be compared to other studies around the world.

Keywords: Botswana, dam, environmental impact assessment, GIS, normalized vegetation index (NDVI), remote sensing

Procedia PDF Downloads 398

Authors: Helen Sanders, Joshua Cousins

Abstract:

The purpose of this study is to ascertain whether riparian buffer strips could be used to reduce Escherichia Coli (E. coli) runoff into streams in Central New York. Mainstream methods currently utilized to reduce E. coli runoff include fencing and staggered fertilizing plans for agriculture. These methods still do not significantly limit E. coli and thus, pose a serious health risk to individuals who swim in contaminated waters or consume contaminated produce. One additional method still in research development involves the planting of vegetated riparian buffers along waterways. Currently, riparian buffer strips are primarily used for filtration of nitrate and phosphate runoff to slow erosion, regulate pH and, improve biodiversity within waterways. For my research, four different stream sites were selected for the study, in which rainwater runoff was collected at both the riparian buffer and the E. coli sourced runoff upstream. Preliminary results indicate that there is an average 70% decrease in E. coli content in streams at the riparian buffer strips compared to upstream runoff. This research could be utilized to include vegetated buffer planting as a method to decrease manure runoff into essential waterways.

Keywords: Escherichia coli, riparian buffer strips, vegetated riparian buffers, runoff, filtration

Procedia PDF Downloads 166