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Tang J, Chen Y, He L, Li Y, Li H, Sun F, Liu Y. Effect of hydrochar from sludge mixed with coffee grounds on the immobilization of Cu, Cr and Ni in soil. ENVIRONMENTAL TECHNOLOGY 2024:1-13. [PMID: 39138577 DOI: 10.1080/09593330.2024.2391077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Accepted: 08/04/2024] [Indexed: 08/15/2024]
Abstract
In this study, hydrochars were prepared at varying temperatures with distinct mixing ratio, and then the hydrochars were characterized and evaluated for heavy metals to ascertain its potential as a soil conditioner. The application of elevated temperatures resulted in a reduction in the yield of hydrochars, whereas the incorporation of coffee grounds led to an increase in the yield. The blended hydrochar displays elevated ash, fixed carbon, and diminished H/C, O/C, and (O + N)/C ratios, indicating enhanced stability in soil treatment and potential for enhanced soil fertility. The application of hydrothermal carbonization facilitated the stabilization of heavy metals within the sewage sludge, with the stabilizing effect being enhanced by the addition of coffee grounds. Following the application of SCC as a soil conditioner to the heavy metal-contaminated soil for a period of 90 days, it was observed that the heavy metals Cu, Cr, and Ni present in the contaminated soil underwent a transition from an unstable to a stable speciation. Of the treatments tested, AK15 was identified as the most effective, demonstrating a significant reduction in the risk of leaching and biotoxicity associated with Cu, Cr, and Ni in the contaminated soil.
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Affiliation(s)
- Jingxiang Tang
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, People's Republic of China
| | - Yu Chen
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, People's Republic of China
| | - Liwenze He
- Department of Civil Engineering, Chengdu Technological University, Chengdu, People's Republic of China
| | - Yanjun Li
- College of Environmental Sciences, Sichuan Agricultural University, Chengdu, People's Republic of China
| | - Haiquan Li
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, People's Republic of China
| | - Fei Sun
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, People's Republic of China
| | - Ying Liu
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, People's Republic of China
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Liu X, Tan Q, Wang P, Deng P, Peng L, Xu Y, Yuan S, Dai X. Pre-drying limitedly affected the yield, fuel properties, pyrolysis and combusion behavior of sewage sludge hydrochar. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 184:63-71. [PMID: 38795541 DOI: 10.1016/j.wasman.2024.05.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 04/30/2024] [Accepted: 05/21/2024] [Indexed: 05/28/2024]
Abstract
While pre-drying of sewage sludge prior to hydrothermal carbonization is rarely practiced, various pre-drying methods have been performed in literature at lab-scale for convenient solid-to-liquid ratio adjustment. This has created a barrier for comparing hydrochar quality between different studies. Given pre-drying can destroy the floc structure of sewage sludge, we hypothesize that pre-drying may promote the hydrolysis step during hydrothermal carbonization process, resulting in improved hydrochar quality with low nitrogen content. In the current study, the influence of different pre-drying methods (freeze-dry, air-dry and vacuum-dry at 70 °C and 105 °C) on the subsequent hydrothermal carbonization of sewage sludge at 220 °C was assessed in terms of sewage sludge and hydrochar's chemical composition, fuel properties, pyrolysis and combustion behavior, as well as the characterization of the liquid phase. The results indicate that although pre-drying impacts sewage sludge's chemical composition, pyrolysis and combustion behavior, no significant differences exist in the yield, chemical composition, fuel properties, and pyrolysis and combustion behavior of the hydrochar. Therefore, the use of pre-drying would not affect the hydrothermal carbonization process of sewage sludge, and a comparison can be made on hydrochar quality between different studies with or without pre-drying.
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Affiliation(s)
- Xiaoguang Liu
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Qingtong Tan
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Peisheng Wang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Peiyue Deng
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Ling Peng
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yaman Xu
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; School of Life Sciences, Jinggangshan University, Ji'an 343009, China
| | - Shijie Yuan
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
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Yang X, Wang B, Zhang P, Song X, Cheng F. Adsorption and reduction of Cr(VI) by N, S co-doped porous carbon from sewage sludge and low-rank coal: Combining experiments and theoretical calculations. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169265. [PMID: 38086485 DOI: 10.1016/j.scitotenv.2023.169265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/21/2023] [Accepted: 12/08/2023] [Indexed: 12/17/2023]
Abstract
Herein, a novel N, S co-doped porous carbon (S5C5-AC) for Cr(VI) removal was prepared by co-hydrothermal carbonization (HTC) of sewage sludge (SS) and low-rank coal (LC) combining with KOH modification. The results showed that S5C5-AC had excellent adsorption performance on Cr(VI), and lower pH value, higher initial concentration and longer contact time were beneficial for Cr(VI) adsorption. The adsorption kinetics and isotherms revealed that Cr(VI) adsorption by S5C5-AC was homogeneous and dominated by chemisorption. The adsorption isotherm showed that the maximum equilibrium adsorption capacity of S5C5-AC for Cr(VI) was 382.04 mg/g at 25 °C. Furthermore, the results showed that the main mechanisms for Cr(VI) removal were the pore filling, electrostatic interaction and reduction. Moreover, the electron transfer mechanism during the adsorption and reduction process was further explored at the molecular and electronic levels by density functional theory (DFT) and front orbital theory (FOT) simulations. The analysis of DFT and FOT indicated that the synergistic effect between S and N functional groups was exhibited during the Cr(VI) removal process. Considering the existence of synergistic effects between N and S functional groups during adsorption, the S and N content and form were modified collaboratively. Increasing the relative content of pyrrolic N may be the most effective pathway for improving removal performance. Besides that, S5C5-AC exhibited excellent adsorption capacity over a high coexisting ion concentration range and various actual water bodies and regeneration performance, which indicated that S5C5-AC had promising potential for the remediation of wastewater in industrial applications.
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Affiliation(s)
- Xiaoyang Yang
- Engineering Research Center of CO(2) Emission Reduction and Resource Utilization - Ministry of Education of the People's Republic of China, Institute of Resources and Environment Engineering, Shanxi University, Taiyuan 030006, China
| | - Baofeng Wang
- Engineering Research Center of CO(2) Emission Reduction and Resource Utilization - Ministry of Education of the People's Republic of China, Institute of Resources and Environment Engineering, Shanxi University, Taiyuan 030006, China.
| | - Peng Zhang
- Engineering Research Center of CO(2) Emission Reduction and Resource Utilization - Ministry of Education of the People's Republic of China, Institute of Resources and Environment Engineering, Shanxi University, Taiyuan 030006, China
| | - Xutao Song
- Engineering Research Center of CO(2) Emission Reduction and Resource Utilization - Ministry of Education of the People's Republic of China, Institute of Resources and Environment Engineering, Shanxi University, Taiyuan 030006, China
| | - Fangqin Cheng
- Engineering Research Center of CO(2) Emission Reduction and Resource Utilization - Ministry of Education of the People's Republic of China, Institute of Resources and Environment Engineering, Shanxi University, Taiyuan 030006, China.
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Rathika K, Kumar S, Yadav BR. Enhanced energy and nutrient recovery via hydrothermal carbonisation of sewage sludge: Effect of process parameters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167828. [PMID: 37839482 DOI: 10.1016/j.scitotenv.2023.167828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/07/2023] [Accepted: 10/12/2023] [Indexed: 10/17/2023]
Abstract
Integration of waste management with energy and resource recovery is being widely explored to achieve sustainability. To achieve this, sewage sludge was treated with hydrothermal carbonisation (HTC) at temperatures ranging from 180 °C-260 °C with an increment of 20 °C for three different duration of 1 h, 3 h, and 5 h. The energy and resource recovery potential of the HTC treatment was evaluated through of hydrochar (HC) and process water (PW) properties. Dehydration and decarboxylation reactions resulted in reduced H/C and O/C atomic ratios of 1.35 and 0.45 respectively in HC-260-3, exhibiting peat-like propertied. The calorific value of HC-260-5 was enhanced to 5.9 MJ/kg (increase of 25.8 %) due to the combined effect of H/C and O/C atomic ratios, increased volatile organics and fixed carbon. A maximum energy recovery efficiency of 82.44 % was realised at 240 °C for 3 h rendering it the optimal process condition to ensure energy enrichment. Thermogravimetric analysis (TGA) of HC samples indicated an enhanced combustion behaviour with an increased HTC severity. The elevated levels of volatile fatty acids (VFAs) in PW (maximum 2296 mg/L) made it viable for energy recovery in anaerobic digestion units. Additionally, the PW contains significant concentrations of N and P (2091.68 mg/L and 40.51 mg/L, respectively), indicating enhanced resource/nutrient recovery potential.
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Affiliation(s)
- K Rathika
- CSIR-National Environmental Engineering Research Institute, Nagpur 440020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sunil Kumar
- CSIR-National Environmental Engineering Research Institute, Nagpur 440020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Bholu Ram Yadav
- CSIR-National Environmental Engineering Research Institute, Nagpur 440020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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