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Li N, Ma H, Wang G, Ma X, Deng J, Yuan S. Efficient extraction and formation mechanism of fulvic acid from lignite: Experimental and DFT studies. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 365:121650. [PMID: 38968881 DOI: 10.1016/j.jenvman.2024.121650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 06/18/2024] [Accepted: 06/28/2024] [Indexed: 07/07/2024]
Abstract
Enhancing the coal-based fulvic acid (FA) yield through the effect of oxidation methods was of great importance. However, the realization of an efficient and environmentally friendly method for the preparation of FA, along with understanding of its formation mechanism, remains imperative. Herein, coal-based FA was prepared by oxidizing lignite with H2O2 and NaOH/KOH. The experimental data showed that ML lignite was pickled with HCl, metal ions such as iron, aluminum, and calcium can be removed, and this lignite is used as raw material, the reaction time was 150 min, the reaction temperature was 50 °C, and the volume ratio of H2O2 (30%) to KOH (3 mol/L) was 1:1, the effect of H2O2 and KOH on FA extraction was the best. The coal-based FA yield could reach 60.49%. The addition of silicone defoaming agent during the experiment resulted in a significant diminished the presence of bubbles and prevent the production of CO2. A decrease in N2 content was detected by GC. The FTIR, XPS, Py-GC/MS and other characterization results showed that FA has more polar functional groups (-COOH, -OH), and it contains more O-CO structure. Consequently, a greater quantity of FA molecules is generated during the reaction process. Moreover, the partial Gibbs free energies during the formation process of coal-based FA were calculated by density-functional theory (DFT). The highest energy required for free radicals was found to be between 1.3 and 1.7 eV. This study would provide theoretical support for exploring the FA formation process and the promotion of lignite humification by adding H2O2 or alkali to lignite.
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Affiliation(s)
- Na Li
- School of Chemical Science and Engineering, Key Laboratory of Medicinal Chemistry for Natural Resource-Ministry of Education, National Demonstration Center for Experimental Chemistry and Chemical Engineering Education, Yunnan Key Laboratory of Carbon Neutrality and Green Low-carbon Technologies, Yunnan University, 2 North Cuihu Road, 650091, Kunming, Yunnan, China.
| | - Hang Ma
- R&D Center. Yunnan Yuntianhua CO., LTD, NO.1417 Dian Lake Road, 650228, Kunming, China.
| | - Guodong Wang
- R&D Center. Yunnan Yuntianhua CO., LTD, NO.1417 Dian Lake Road, 650228, Kunming, China.
| | - Xunmeng Ma
- School of Chemical Science and Engineering, Key Laboratory of Medicinal Chemistry for Natural Resource-Ministry of Education, National Demonstration Center for Experimental Chemistry and Chemical Engineering Education, Yunnan Key Laboratory of Carbon Neutrality and Green Low-carbon Technologies, Yunnan University, 2 North Cuihu Road, 650091, Kunming, Yunnan, China.
| | - Jin Deng
- School of Chemical Science and Engineering, Key Laboratory of Medicinal Chemistry for Natural Resource-Ministry of Education, National Demonstration Center for Experimental Chemistry and Chemical Engineering Education, Yunnan Key Laboratory of Carbon Neutrality and Green Low-carbon Technologies, Yunnan University, 2 North Cuihu Road, 650091, Kunming, Yunnan, China.
| | - Shenfu Yuan
- School of Chemical Science and Engineering, Key Laboratory of Medicinal Chemistry for Natural Resource-Ministry of Education, National Demonstration Center for Experimental Chemistry and Chemical Engineering Education, Yunnan Key Laboratory of Carbon Neutrality and Green Low-carbon Technologies, Yunnan University, 2 North Cuihu Road, 650091, Kunming, Yunnan, China.
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Gong X, Sawut A, Simayi R, Wang Z, Feng Y. Preparation of modified humic acid/TiO 2/P(AA- co-AM) nanocomposite hydrogels with enhanced dye adsorption and photocatalysis. SOFT MATTER 2024; 20:2937-2954. [PMID: 38466149 DOI: 10.1039/d3sm01749d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
A novel composite hydrogel with exceptional adsorption and photocatalytic properties was synthesized using modified coal-based humic acid (HA-C), modified titanium dioxide (TiO2) nanoparticles, acrylic acid (AA), and acrylamide (AM) as precursors. The modification of HA-C and TiO2 significantly enhances the structural support provided by the hydrogel for photocatalytic components. Moreover, we investigated the effects of monomer ratio, dye concentration, temperature, and pH on the material properties. Additionally, we tested the mechanical strength, swelling behavior, and reusability of the hydrogels. The composite hydrogel's adsorption performance and synergistic adsorption-photocatalytic performance were evaluated based on its removal rate for both absorbed and degraded methylene blue (MB). Remarkably, incorporating HA-C greatly improved the adsorption efficiency of the composite hydrogel for methylene blue to a maximum capacity of 1490 mg g-1. Furthermore, TiO2 nanoparticles in the structure promoted MB degradation with an efficiency exceeding 96.5%. The hydrogel exhibited excellent recoverability and reusability through nine cycles of adsorption/desorption as well as six cycles of degradation.
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Affiliation(s)
- Xuankun Gong
- State Key Laboratory of Chemistry and Utilizationof Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, 830017, Xinjiang, China.
| | - Amatjan Sawut
- State Key Laboratory of Chemistry and Utilizationof Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, 830017, Xinjiang, China.
| | - Rena Simayi
- State Key Laboratory of Chemistry and Utilizationof Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, 830017, Xinjiang, China.
| | - Ziyue Wang
- State Key Laboratory of Chemistry and Utilizationof Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, 830017, Xinjiang, China.
| | - Yurou Feng
- State Key Laboratory of Chemistry and Utilizationof Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, 830017, Xinjiang, China.
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Wang G, Bo W, Wan K, Fan J, Miao Z, Xue S. Remediation of the soil contaminated by heavy metals with nano-hydroxy iron phosphate coated with fulvic acid. ENVIRONMENTAL TECHNOLOGY 2023; 44:4123-4135. [PMID: 35587734 DOI: 10.1080/09593330.2022.2080001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Abstract
Heavy metals pose a serious threat and damage to ecological health when released into the environment. n-HFP is usually used to remediate soils contaminated with heavy metals, but its ability to solidify heavy metals is limited. FA has good ability to trap heavy metals due to its abundant oxygen-containing functional groups. However, the solubility of FA in water limits its application in the field of heavy metal removal. In this paper, n-HFP@FA was prepared by co-precipitation method. Through FT-IR and BET analysis, the oxygen-containing functional groups and specific surface area of n-HFP@FA increased due to the addition of FA. The adsorption behaviour of n-HFP@FA on Pb, Cd, and Cu followed the pseudo-second-order and Langmuir isotherm models. In addition, the maximum adsorption capacities of n-HFP@FA for Pb, Cd, and Cu were 371.1, 190.5, and 129.75 mg/g, respectively. As shown by FT-IR and XPS analysis, the main mechanisms of Pb, Cd and Cu removal by n-HFP@FA are: complexation, electrostatic and precipitation. The n-HFP@FA showed high removal rates of Pb, Cd, and Cu in soil leachates of different pH. In the soil remediation experiments, the BCR method and Pearson correlation analysis showed that the acid-soluble, reducible and oxidizable fractions of Pb, Cd, and Cu in the soil were effectively converted into a more stable residual fraction. This study opens up a prospect for the application of n-HFP@FA composites in the remediation of contaminated soil.
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Affiliation(s)
- Guoqiang Wang
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, People's Republic of China
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou, People's Republic of China
| | - Wenting Bo
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, People's Republic of China
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou, People's Republic of China
| | - Keji Wan
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou, People's Republic of China
| | - Jinjin Fan
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, People's Republic of China
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou, People's Republic of China
| | - Zhenyong Miao
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, People's Republic of China
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou, People's Republic of China
| | - Shuwen Xue
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, People's Republic of China
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou, People's Republic of China
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Li Y, Chen X, Zhuo Z, Li X, Sun T, Liu P, Lei T. Co-Thermal Oxidation of Lignite and Rice Straw for Synthetization of Composite Humic Substances: Parametric Optimization via Response Surface Methodology. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16875. [PMID: 36554757 PMCID: PMC9778861 DOI: 10.3390/ijerph192416875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 06/17/2023]
Abstract
In this study, Baoqing lignite (BL) and rice straw (RS), which were the representatives of low-rank coal and biomass, were co-thermally oxidized to produce composite humic substances (HS), including humic acid (HA) and fulvic acid (FA). Taking HS content as the output response, the co-thermally oxidizing conditions were optimized through single factor experiment and response surface methodology (RSM). The structures of HA and FA prepared under optimized conditions were analyzed by SEM, UV, and FTIR. Results showed that HS content was clearly influenced by the material ratio, oxidation time, and oxidation temperature, as well as their interactions. The optimized co-thermal oxidization condition was as follows: BL and RS pretreated with a material ratio of 0.53, oxidation time of 59.50 min, and oxidation temperature of 75.63 °C. Through verification, the experimental value (62.37%) had a small relative error compared to the predicted value (62.27%), which indicated that the developed models were fit and accurate. The obtained HA had a tightly packed block structure; FA had a loosely spherical shape. The molecular weight of FA was 2487 Da and HA was 20,904 Da; both had a smaller molecular weight than that reported in other literature. FA showed strong bands at 1720 cm-1, thus confirming the presence of more oxygen-containing functional groups. The appearance of double peaks at 2900~2980 cm-1 indicated that HA contains more aliphatic chains. The co-thermal oxidation of BL and RS gives a new method for the synthesis of HS, and the optimization of co-thermal oxidation conditions will provide fundamental information for the industrialization of composite HS.
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Affiliation(s)
- Yanling Li
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization Technology, Institute of Urban and Rural Mines, Changzhou University, Changzhou 213164, China
| | - Xi Chen
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization Technology, Institute of Urban and Rural Mines, Changzhou University, Changzhou 213164, China
| | - Zhen Zhuo
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization Technology, Institute of Urban and Rural Mines, Changzhou University, Changzhou 213164, China
| | - Xueqin Li
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization Technology, Institute of Urban and Rural Mines, Changzhou University, Changzhou 213164, China
- Department of Chemical Engineering for Energy Resources, East China University of Science and Technology, Shanghai 200237, China
| | - Tanglei Sun
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization Technology, Institute of Urban and Rural Mines, Changzhou University, Changzhou 213164, China
| | - Peng Liu
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization Technology, Institute of Urban and Rural Mines, Changzhou University, Changzhou 213164, China
| | - Tingzhou Lei
- Changzhou Key Laboratory of Biomass Green, Safe & High Value Utilization Technology, Institute of Urban and Rural Mines, Changzhou University, Changzhou 213164, China
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