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Yap BJT, Heng GC, Ng CA. Electrochemical oxidation process on palm oil mill effluent waste activated sludge: optimization by response surface methodology. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 86:1122-1134. [PMID: 36358050 DOI: 10.2166/wst.2022.255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Biological-based treatment as the conventional treatment for palm oil mill effluent (POME) in open-ponding system face a well known rate-limiting step which is hydrolysis. In this study, electrochemical oxidation (EO) by a ruthenium oxide-coated titanium (Ti/RuO2) electrode was introduced as a pre-treatment for POME waste activated sludge (WAS). Surface morphology and elemental analysis were investigated using field emission scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. Response surface methodology type central composite design was used in this study to understand the relationship between the independent and dependent variables. Analysis of variance (ANOVA) was used to validate the model of the studied variables. The correlation coefficients (R2) indicated a close agreement between the experimental results and the predicted values, with high R2 values of 0.9044-0.9773. Multiple response optimization suggested that the range of current density (17-27 mA/cm2) and electrolysis time (55-75 min) at a fixed concentration of sodium chloride (10 g/L), resulted in mixed liquor volatile suspended solids (MLVSS) removal >20%, capillary suction timer (CST) reduction >43%, extracellular polymeric substances (EPS) increment <19% and soluble chemical oxygen demand (sCOD) increment >25%. EO appears to be an efficient pre-treatment as well as practical way to improve the POME WAS disintegration and dewaterability.
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Affiliation(s)
- Branda Jian Tong Yap
- Department of Environmental Engineering, Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, Kampar 31900, Perak, Malaysia
| | - Gan Chin Heng
- Department of Civil Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, Kajang 43000, Selangor, Malaysia E-mail:
| | - Choon Aun Ng
- Department of Environmental Engineering, Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, Kampar 31900, Perak, Malaysia
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Zhou H, Zhang D, Gong X, Feng Z, Shi M, Liu Y, Zhang C, Luan P, Zhang P, Fan F, Li R, Li C. A Dual-Ligand Strategy to Regulate the Nucleation and Growth of Lead Chromate Photoanodes for Photoelectrochemical Water Splitting. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2110610. [PMID: 35589018 DOI: 10.1002/adma.202110610] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 05/10/2022] [Indexed: 06/15/2023]
Abstract
Photoelectrochemical (PEC) water splitting for renewable hydrogen production has been regarded as a promising solution to utilize solar energy. However, most photoelectrodes still suffer from poor film quality and poor charge separation properties, mainly owing to the possible formation of detrimental defects including microcracks and grain boundaries. Herein, a molecular coordination engineering strategy is developed by employing acetylacetone (Acac) and poly(ethylene glycol) (PEG) dual ligands to regulate the nucleation and crystal growth of the lead chromate (PbCrO4 ) photoanode, resulting in the formation of a high-quality film with large grain size, well-stitched grain boundaries, and reduced oxygen vacancies defects. With these efforts, the nonradiative charge recombination is efficiently suppressed, leading to the enhancement of its charge separation efficiency from 47% to 90%. After decorating with Co-Pi cocatalyst, the PbCrO4 photoanode achieves a photocurrent density of 3.15 mA cm-2 at 1.23 V (vs RHE under simulated AM1.5G) and an applied bias photon-to-current efficiency (ABPE) of 0.82%. This work provides a new strategy to modulate the nucleation and growth of high-quality photoelectrodes for efficient PEC water splitting.
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Affiliation(s)
- Hongpeng Zhou
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
| | - Deyun Zhang
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Xiangnan Gong
- Analytical and Testing Center of Chongqing University, Chongqing, 400044, P. R. China
| | - Zhendong Feng
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Ming Shi
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Yang Liu
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
| | - Chengbo Zhang
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Peng Luan
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
| | - Pengfei Zhang
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
| | - Fengtao Fan
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
| | - Rengui Li
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
| | - Can Li
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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