Search results for: Huihui Li

Authors: Huihui Zhang, Zhongzhi Zhang

Abstract:

Coagulation/flocculation is regarded a simple and effective wastewater treatment technology. Chlorine-containing coagulants may release chloride ions into the wastewater, causing corrosion. A green chlorine-free coagulant of polyaluminum ferric silicate (PSAF) was prepared by the copolymerization method to treat oily refractory wastewaters. Results showed that the highest removal efficiency of turbidity and chemical oxygen demand (COD) achieved 97.4% and 93.0% at a dosage of 700 mg/L, respectively. After PSAF coagulation, the chloride ion concentration was also almost the same as that in the raw wastewater. Thus, the chlorine-free coagulant is highly efficient and does not introduce additional chloride ions into the wastewater, avoiding corrosion.

Keywords: coagulation, chloride-free coagulant, oily refractory wastewater, coagulation performance

Procedia PDF Downloads 238

Authors: Raghabendra Yadav, Baochun Chen, Huihui Yuan, Zhibin Lian

Abstract:

Concrete Filled Steel Tube (CFST) columns are widely used in Civil Engineering Structures due to their abundant properties. CFST-RC column is a built up column in which CFST members are connected with RC web. The CFST-RC column has excellent static and earthquake resistant properties, such as high strength, high ductility and large energy absorption capacity. CFST-RC columns have been adopted as piers in Ganhaizi Bridge in high seismic risk zone with a highest pier of 107m. The experimental investigation on scaled models of similar type of the CFST-RC pier are carried out. The experimental investigation on scaled models of similar type of the CFST-RC pier are carried out. Under cyclic loading, the hysteretic performance of CFST-RC columns, such as failure modes, ductility, load displacement hysteretic curves, energy absorption capacity, strength and stiffness degradation are studied in this paper.

Keywords: CFST, cyclic load, Ganhaizi bridge, seismic performance

Procedia PDF Downloads 265

Authors: Raghabendra Yadav, Baochun Chen, Huihui Yuan, Zhibin Lian

Abstract:

Pseudo-dynamic test (PDT) method is an advanced seismic test method that combines loading technology with computer technology. Large-scale models or full scale seismic tests can be carried out by using this method. CFST-RC columns are used in civil engineering structures because of their better seismic performance. A CFST-RC column is composed of four CFST limbs which are connected with RC web in longitudinal direction and with steel tube in transverse direction. For this study, a CFST-RC pier is tested under Four different earthquake time histories having scaled PGA of 0.05g. From the experiment acceleration, velocity, displacement and load time histories are observed. The dynamic magnification factors for acceleration due to Elcentro, Chi-Chi, Imperial Valley and Kobe ground motions are observed as 15, 12, 17 and 14 respectively. The natural frequency of the pier is found to be 1.40 Hz. The result shows that this type of pier has excellent static and earthquake resistant properties.

Keywords: bridge pier, CFST-RC pier, pseudo dynamic test, seismic performance, time history

Procedia PDF Downloads 203

Authors: Huihui Li, Chuan Zhao

Abstract:

Proton exchange membrane water electrolyzer (PEMWE) offers a scalable route to green hydrogen production but is hindered by the instability of acidic oxygen evolution reaction (OER) catalysts. Although Ru-based materials show promise, their high cost and susceptibility to corrosion limit practical deployment. Here, we report a single-atom Ru doped Co3O4 catalyst via electrodeposition and cation exchange, where Ru atoms selectively occupy octahedral Co3+ sites. This atomic engineering weakens metal-oxygen (Ru/Co-O) covalency, enhancing structural flexibility to promote the oxide path mechanism (OPM)—bypassing lattice oxygen participation—as confirmed by operando Raman and FT-IR spectroscopy and TMA+ probe experiments. The resulting catalyst achieves an overpotential of 173 mV at 10 mA cm-2 in 0.5 M H2SO4 and operates stably for 2623 hours (>3.6 months) with a negligible decay rate of 0.011 mV h-1, outperforming most noble metal-doped Co3O4 benchmarks. Crucially, the ultralow Ru loading (4.46 wt.%) reduces noble metal costs to USD $0.00064 cm-2. During prolonged operation, in situ formation of RuO2/Ru-doped Co3O4 heterojunction further stablizes the catalyst, with Ru-doped Co3O4 acting as an electron reservoir to suppress Ru overoxidation. Membrane electrode assembly tests further validate its practicality for proton exchange membrane electrolyzers (PEMWE). This work demonstrates that tailoring metal-oxygen covalency through single-atom doping can strategically regulate OER pathways and interfacial dynamics, offering a generalizable design principle for durable acidic electrocatalysts. Our findings pave the way for developing self-optimizing heterostructures and oxyphilic dopant libraries to advance green hydrogen technologies.

Keywords: acidic oxygen evolution reaction, metal-oxygen covalency, oxophilic element, structural flexibility

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