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Wang J, Wei X, Kong H, Zheng X, Guo H. Hydrothermal Ammonia Carbonization of Rice Straw for Hydrochar to Separate Cd(II) and Zn(II) Ions from Aqueous Solution. Polymers (Basel) 2023; 15:4548. [PMID: 38231969 PMCID: PMC10708519 DOI: 10.3390/polym15234548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/09/2023] [Accepted: 11/16/2023] [Indexed: 01/19/2024] Open
Abstract
Hydrochar is considered to be a good adsorbent for the separation of metal ions from aqueous solutions. However, the yield of hydrochar from raw straw is generally low, because the hydrothermal carbonization occurs via dehydration, polymerization, and carbonization. In this work, various hydrochar samples were prepared from rice straw with nitrogen and phosphorus salt; moreover, toilet sewage was used instead of nitrogen, and phosphorus salt and water were used to promote the polymerization and carbonization process. The modified carbon was characterized using XRD, XPS, SEM, and FTIR, and the adsorption capacity was investigated. A significant increase in hydrochar yield was observed when toilet sewage was used as the solvent in the hydrothermal carbonization process. The adsorption capacity of N/P-doped rice straw hydrochar for Cd2+ and Zn2+ metal ions was 1.1-1.4 times higher than that those using the rice straw hydrochar. The Langmuir models and pseudo-second-order models described the metal adsorption processes in both the single and binary-metal systems well. The characterization results showed the contribution of the surface complexation, the electrostatic interaction, the hydrogen bond, and the ion exchange to the extraction of Cd2+ and Zn2+ using N/P-doped rice straw hydrochar.
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Affiliation(s)
- Jiarui Wang
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.W.); (X.W.); (H.K.)
- Key Laboratory for Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Xiaocheng Wei
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.W.); (X.W.); (H.K.)
- Key Laboratory for Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Hao Kong
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.W.); (X.W.); (H.K.)
- Key Laboratory for Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Xiangqun Zheng
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.W.); (X.W.); (H.K.)
- Key Laboratory for Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
- Institute of Environment and Sustainable Development in Agriculture, CAAS, Beijing 100081, China
| | - Haixin Guo
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.W.); (X.W.); (H.K.)
- Key Laboratory for Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
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Mohrazi A, Ghasemi-Fasaei R, Mojiri A, Safarzadeh Shirazi S. Optimization of LDO-Pectin Synthesis Conditions for the Removal of Metals from Wastewater: A Comparison of Response Surface Methods and Taguchi Approaches. Polymers (Basel) 2023; 15:3778. [PMID: 37765632 PMCID: PMC10537719 DOI: 10.3390/polym15183778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
With the continuous growth of industrialization, the presence of heavy metals (HMs) in the environment has become a critical issue, necessitating cost-effective and efficient techniques for their removal. The present study aimed to determine the optimal preparation conditions for synthesizing pectin (PC) as a polymer sorbent, combined with Magnesium (Mg) Aluminum (Al) layered double oxides (LDOs), using a fast and facile co-precipitation method. Both the response surface method (RSM) and the Taguchi method were employed to optimize the influence of key independent variables, including the molar ratio of cations Mg:Al, the ratio of pectin to LDO, and the temperature for removing multiple elements from wastewater. The results indicated that RSM is more accurate and examines more interactions, while Taguchi reduces the number of tests and is more economical than RSM. However, both statistical methods showed good potential for predicting the adsorption capacity (Qe) of HMs. The optimal preparation conditions were identified as a molar ratio of 3:1, a ratio of pectin to LDO of 7% w/w, and a temperature of approximately 600 °C. In conclusion, the application of RSM and Taguchi approaches was found to be feasible and effective in optimizing the preparation conditions of modified LDO, which can be utilized as a potential adsorbent for removing multiple elements from wastewater.
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Affiliation(s)
- Ava Mohrazi
- Department of Soil Science, School of Agriculture, Shiraz University, Shiraz 71348-14336, Iran
| | - Reza Ghasemi-Fasaei
- Department of Soil Science, School of Agriculture, Shiraz University, Shiraz 71348-14336, Iran
| | - Amin Mojiri
- Envirowise Research Associate, Christchurch 8053, New Zealand
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