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Yin G, Guan P, Wang YH, Zhang P, Qu B, Xu S, Zhang G, He C, Shi Q, Wang J. Temporal Variations in Fire Impacts on Characteristics and Composition of Soil-Derived Dissolved Organic Matter at Qipan Mountain, China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:13772-13782. [PMID: 39058895 DOI: 10.1021/acs.est.4c00446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Dissolved organic matter (DOM), the most reactive fraction of forest soil organic matter, is increasingly impacted by wildfires worldwide. However, few studies have quantified the temporal changes in soil DOM quantity and quality after fire. Here, soil samples were collected after the Qipan Mountain Fire (3-36 months) from pairs of burned and unburned sites. DOM contents and characteristics were analyzed using carbon quantification and various spectroscopic and spectrometric techniques. Compared with the unburned sites, burned sites showed higher contents of bulk DOM and most DOM components 3 months after the fire but lower contents of them 6-36 months after the fire. During the sharp drop of DOM from 3 to 6 months after the fire, carboxyl-rich alicyclic molecule-like and highly unsaturated compounds had greater losses than condensed aromatics. Notably, the burned sites had consistently higher abundances of oxygen-poor dissolved black nitrogen and fluorescent DOM 3-36 months after the fire, particularly the abundance of pyrogenic C2 (excitation/emission maxima of <250/∼400 nm) that increased by 150% before gradually declining. This study advances the understanding of temporal variations in the effects of fire on different soil DOM components, which is crucial for future postfire environmental management.
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Affiliation(s)
- Gege Yin
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Ping Guan
- Liaoning Key Laboratory for Biological Invasions and Global Changes, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
| | - Ying-Hui Wang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Peng Zhang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Bo Qu
- Liaoning Key Laboratory for Biological Invasions and Global Changes, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
| | - Shujun Xu
- Liaoning Key Laboratory for Biological Invasions and Global Changes, Shenyang Agricultural University, Shenyang, Liaoning 110866, China
| | - Gan Zhang
- State Key Laboratory of Organic Geochemistry, Guangdong Province Key Laboratory of Environmental Protection and Resources Utilization, and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong 510640, China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
| | - Junjian Wang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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Shu Z, Liu Q, Liu E, Pan Z, Yan S, Zhang L, Song W, Wang Z. Overlooked role of aqueous chromate (VI) as a photosensitizer in enhancing the photochemical reactivity of ferrihydrite and production of hydroxyl radical. JOURNAL OF HAZARDOUS MATERIALS 2024; 466:133557. [PMID: 38309168 DOI: 10.1016/j.jhazmat.2024.133557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/26/2023] [Accepted: 01/16/2024] [Indexed: 02/05/2024]
Abstract
The reactive oxygen species (ROS) photochemically generated from natural iron minerals have gained significant attention. Amidst the previous studies on the impact of heavy metal ions on ROS generation, our study addresses the role of the anion Cr(VI), with its intrinsic photoactivity, in influencing ROS photochemical generation with the co-presence of minerals. We investigated the transformation of inorganic/organic pollutants (Cr(VI) and benzoic acid) at the ferrihydrite interface, considering sunlight-mediated conversion processes (300-1000 nm). Increased photochemical reactivity of ferrihydrite was observed in the presence of aqueous Cr(VI), acting as a photosensitizer. Meanwhile, a positive correlation between hydroxyl radical (•OH) production and concentrations of aqueous Cr(VI) was observed, with a 650% increase of •OH generation at 50 mg L-1 Cr(VI) compared to systems without Cr(VI). Our photochemical batch experiments elucidated three potential pathways for •OH photochemical production under varying wet chemistry conditions: (1) ferrihydrite hole-mediated pathway, (2) chromium intermediate O-I-mediated pathway, and (3) chromium intermediates CrIV/V-mediated pathway. Notably, even in the visible region (> 425 nm), the promotion of aqueous Cr(VI) on •OH accumulation was observed in the presence of ferrihydrite and TiO2 suspensions, attributed to Cr(VI) photosensitization at the mineral interface. This study sheds light on the overlooked role of aqueous Cr(VI) in the photochemical reactivity of minerals, thereby enhancing our understanding of pollutant fate in acid mining-impacted environments.
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Affiliation(s)
- Zhipeng Shu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Qiuyao Liu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Enyang Liu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Zezhen Pan
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Eco-Chongming, Fudan University, Shanghai 200062, China.
| | - Shuwen Yan
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Liwu Zhang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Weihua Song
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Zimeng Wang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Eco-Chongming, Fudan University, Shanghai 200062, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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3
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Guo S, Lu L, Chen B. Effects of carbon-silicon structure on photochemical activity of biochars. CHEMOSPHERE 2024; 347:140719. [PMID: 37967675 DOI: 10.1016/j.chemosphere.2023.140719] [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: 05/13/2023] [Revised: 11/05/2023] [Accepted: 11/12/2023] [Indexed: 11/17/2023]
Abstract
Biochar has raised increasing concerns because of its great environmental impacts. It is known that the photocatalytic property of biochar is related to its carbon component and dissolved black carbon, but the effect of silicon component is ignored, and the effect of silicon and carbon phases was far less studied. This study systematically explored the photochemistry of silicon-rich and silicon-deficient biochar under light irradiation by using hexavalent chromium (Cr(VI)) and sulfadiazine as representative pollutants for photoreduction and photooxidation, respectively. It was found that biochar had photoreduction activity under the enhancement of electron donors, and 80.1% Cr(VI) can be removed by biochar with crystalline silicon and carbon (i.e., RH900) after 12 h irradiation. Meanwhile after low temperature pyrolysis, biochar with amorphous silicon and carbon (i.e., RH600) had great photooxidation capacity, and 71.90% organic pollutant was degraded within 24 h. The reaction was illustrated by transient photocurrent response, and hydroxyl radical generation measurement, and other tests. A new photochemical mechanism of the synergy between silicon and carbon model was proposed to elucidate the redox reactions of pollutants under the light. Graphitic carbon or crystalline silicon formed under high temperature played a role of valence band which was excited under light irradiation and the effect of electron donors to benefit photoreduction, while amorphous silicon formed under low temperature facilitated photooxidation process by increasing reactive oxygen species concentration. This study provided a gist for biochar production and application in the field of photocatalysis, and contributed to the broader understanding of biochar geochemical behavior in natural sunlit system.
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Affiliation(s)
- Siwei Guo
- Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, 310058, China.
| | - Lun Lu
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, 510655, China.
| | - Baoliang Chen
- Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, 310058, China.
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Liu D, Liu X, Guo Z, Li Q, Yang J, Xing H, Chen D. Aluminum-Porphyrin Metal-Organic Frameworks for Visible-Light Photocatalytic and Sonophotocatalytic Cr(VI) Reduction. Inorg Chem 2023; 62:19812-19820. [PMID: 37988065 DOI: 10.1021/acs.inorgchem.3c03563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
In this study, four isostructural aluminum-based porphyrin metal-organic frameworks [Al-TCPP(M), M = H2 and Zn] with different morphologies and sizes were synthesized by the hydrothermal method. By adjusting the hydrothermal reaction time and the types of porphyrin ligands, Al-TCPP(M) MOFs exhibited diverse morphologies including tetragonal, rectangular, and carambola-like phase. In view of the introduction of porphyrin ligands and the strong coordination effect of Al-O units, Al-TCPP(M) MOFs exhibited good chemical stability, broad visible light harvesting capability, and fast photogenerated charge response. Four Al-TCPP(M) MOFs exhibited excellent photocatalytic activities for Cr(VI) in aqueous solution. Notably, the regulation to the nanoscale carambola-like morphology of Al-TCPP MOFs and metallization of the porphyrin ligand promoted the Cr(VI) photoreduction reaction where the catalytic activity of metallic carambola-like Al-TCPP increased 1.7 times compared to that of nonmetallic tetragonal MOFs. With the assistance of sonophotocatalysis, the Cr(VI) average reduction rates reached 0.658, 0.542, 0.785, and 0.629 mg·L-1·min-1 for Al-TCPP(H2)-24h, Al-TCPP(H2)-72h, Al-TCPP(Zn)-24h, and Al-TCPP(Zn)-72h, which are 1.2-1.4 times higher than that of photocatalysis. UV-vis absorption spectroscopy, electronic spin resonance, and fluorescence spectroscopy experiments demonstrated that the synergistic effect of photochemistry and sonochemistry promoted the transfer of photogenerated electrons from Al-TCPP(M) to Cr(VI), thus enhancing the catalytic activity. The combination of the sonophotocatalytic technology with aluminum-porphyrin MOFs may become an effective strategy to improve MOF-based photocatalytic systems.
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Affiliation(s)
- Dandan Liu
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, No. 26 Hexing Road, Harbin 150040, China
| | - Xin Liu
- Provincial Key Laboratory of Advanced Energy Materials, College of Chemistry, Northeast Normal University, No. 5268 Renmin Street, Changchun 130024, China
| | - Zhifen Guo
- Jiangsu Key Laboratory for Biofunctional Molecules, School of Life Sciences and Chemical Engineering, Jiangsu Second Normal University, No. 6 Xinhe West Road, Nan Jing 211200, China
| | - Qiang Li
- Inner Mongolia Institute of Synthetic Chemicals, No. 65 Xinhua East Street, Hohhot 010010, China
| | - Jian Yang
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, No. 26 Hexing Road, Harbin 150040, China
| | - Hongzhu Xing
- Provincial Key Laboratory of Advanced Energy Materials, College of Chemistry, Northeast Normal University, No. 5268 Renmin Street, Changchun 130024, China
| | - Dashu Chen
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, No. 26 Hexing Road, Harbin 150040, China
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5
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Tan Y, Sun S, Deng Z, Alvarez PJJ, Qu X. Intrinsic peroxidase-like activity of dissolved black carbon released from biochar. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 898:165347. [PMID: 37419343 DOI: 10.1016/j.scitotenv.2023.165347] [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: 04/16/2023] [Revised: 07/04/2023] [Accepted: 07/04/2023] [Indexed: 07/09/2023]
Abstract
Dissolved black carbon (DBC) is an important constituent of the natural organic carbon pool, influencing the global carbon cycling and the fate processes of many pollutants. In this work, we discovered that DBC released from biochar has intrinsic peroxidase-like activity. DBC samples were derived from four biomass stocks, including corn, peanut, rice, and sorghum straws. All DBC samples catalyze H2O2 decomposition into hydroxyl radicals, as determined by the electron paramagnetic resonance and the molecular probe. Similar to enzymes that exhibit saturation kinetics, the steady-state reaction rates follow the Michaelis-Menten equation. The peroxidase-like activity of DBC is controlled by the ping-pong mechanism, as suggested by parallel Lineweaver-Burk plots. Its activity increases with temperature from 10 to 80 °C and has an optimum at pH 5. The peroxidase-like activity of DBC is positively correlated with its aromaticity as aromatics can stabilize the reactive intermediates. The active sites in DBC also involve oxygen-containing groups, as inferred by increased activity after the chemical reduction of carbonyls. The peroxidase-like activity of DBC has significant implications for biogeochemical processing of carbon and potential health and ecological impacts of black carbon. It also highlights the need to advance the understanding of the occurrence and role of organic catalysts in natural systems.
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Affiliation(s)
- Yi Tan
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210023, China
| | - Su Sun
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210023, China
| | - Zehui Deng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210023, China
| | - Pedro J J Alvarez
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, United States
| | - Xiaolei Qu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210023, China.
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E Z, Liang J, Dong Y, Chao Q, Li P, Fan Q. Different photoreduction processes of Cr(VI) on cellulose-rich and lignin-rich biochar. ENVIRONMENTAL RESEARCH 2023; 236:116819. [PMID: 37541418 DOI: 10.1016/j.envres.2023.116819] [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: 03/13/2023] [Revised: 07/30/2023] [Accepted: 08/02/2023] [Indexed: 08/06/2023]
Abstract
In this study, a series of biochar were prepared via pyrolyzing cellulose-rich pakchoi (PBC) and lignin-rich corncob (CBC) to explore the photoreduction process of Cr(VI). X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy confirmed higher oxygenated functional groups in PBC (48.9%-57.1%), whereas CBC exhibited more aromatization properties due to the stable aromatic network in lignin. For PBC, the valence bands decreased from 1.42 eV to 1.20 eV with the increase of pyrolysis temperature from 300 °C to 500 °C; however, an opposite trend was observed for CBC. The photoreduction of Cr(VI) clearly showed that both PBC and CBC had the best performance at the carbonization temperature of 300 °C (named PBC300 and CBC300). It is noted that PBC300 exhibited the most effective photoreduction of Cr(VI), which was about 1.3 times higher than that of CBC300. The maximum reduction capacities of Cr(VI) were 68.2 mg g-1 on PBC300 and 66.1 mg g-1 on CBC300 at pH∼2.0. Compared with the insoluble char substances, dissolved black carbons made more contributions for Cr(VI) photoreduction, ∼70% in PBC and almost 100% in CBC, which suggested that in the case of PBC, the insoluble char and the corresponding dissolved black carbons play an important role in the photoreduction of Cr(VI). However, only dissolved black carbons contributed to Cr(VI) photoreduction on CBC. As the key reaction pathway, the interfacial electron transport dominated Cr(VI) reduction on PBC and CBC. Moreover, the radical of •O2- had some contribution to the reduction of Cr(VI) only in the PBC system. Interestingly, •OH could promote the photoreduction of Cr(VI) in both PBC and CBC systems, which might be due to the fact that •OH facilitated the formation of small molecule fragments. These findings provide an essential basis for evaluating the environmental impact of photocatalytic behaviors of biochar.
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Affiliation(s)
- Zhengyang E
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jianjun Liang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China; Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, China
| | - Yaqiong Dong
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qian Chao
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ping Li
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China; Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, China
| | - Qiaohui Fan
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China; Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, China.
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Liu L, Wang J, Yang H, Gao D, Cui Y, Chen H, Qin Y, Ye R, Ding X. The critical impacts of pyrochar during 2,4,6-trichlorophenol photochemical remediation process: Cooperation between persistent free radicals and oxygenated functional groups. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 330:121813. [PMID: 37178952 DOI: 10.1016/j.envpol.2023.121813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/15/2023]
Abstract
The widespread use of polychlorophenols poses enormous environmental challenges. Biochar has the potential to accelerate the transformation of polychlorophenols. But the biochar-triggered photochemical decomposition mechanism of polychlorophenols still remains unclear. Herein, the photochemical behavior of pyrochar was comprehensively investigated in 2,4,6-trichlorophenol (TCP) remediation. Researches revealed that persistent free radicals (PFRs) and oxygenated functional groups (OFGs) on the surface of pyrochar cooperatively promoted ROS generation for TCP degradation. PFRs performed a key role of electron-donating and energy transfer in ROS conversion, especially in the activation of H2O2 into •OH. The hydroxyl groups of photosensitive components of pyrochar were photo-excited and provided electrons for enhanced ROS formation as well. With photogenerated ROS involved, more TCP was decomposed through dechlorination under light irradiation than that in the dark, in which 1O2, •OH, and •O2- were the dominant active species. During this process, stronger light intensities (3 W/m2) and shorter light wavelengths (400 nm) can provide more energy for the activation of PFRs and OFGs, promoting the decomposition of TCP. This work casts a new light on the environmental roles of pyrochar in the photochemical removal of polychlorophenol pollutants.
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Affiliation(s)
- Lu Liu
- College of Science, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Jian Wang
- College of Science, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Huijuan Yang
- College of Science, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Di Gao
- College of Science, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Yaya Cui
- College of Science, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Hao Chen
- College of Science, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Yaxin Qin
- School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan, 430205, PR China
| | - Ranfeng Ye
- College of Science, Huazhong Agricultural University, Wuhan, 430070, PR China.
| | - Xing Ding
- College of Science, Huazhong Agricultural University, Wuhan, 430070, PR China
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8
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Ding Z, Zhang W, Liang J, Qiang S, Wang W, Li P, Fan Q. Photoreduction behavior of Cr(VI) on oxidized carbon nanoparticles: From photocatalytic efficiency to oxygenated groups. CHEMOSPHERE 2023; 311:137136. [PMID: 36343728 DOI: 10.1016/j.chemosphere.2022.137136] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/18/2022] [Accepted: 11/02/2022] [Indexed: 06/16/2023]
Abstract
Clarifying the reaction process and specific mechanism between variable-valence elements and oxidized carbon nanoparticles is essential to evaluate the environmental impact of carbon nanomaterials. In this study, the photocatalytic reduction of Cr(VI) on oxidized carbon nanotubes (OCNTs), oxidized graphene ribbons (OGRs), and graphene oxide sheets (GOs) was explored by batch experiments and spectroscopic analyses. The reaction efficiencies strongly depended on the number of oxygenated groups in the oxidized carbon nanoparticles. The abundant oxygenated groups enabled the GOs to exhibit the highest photocatalytic activity, followed by the OGRs and OCNTs. As a result, the photoreduction efficiency of Cr(VI) reached 96% for GOs, whereas those of OGRs and OCNTs were only 40% and 13%, respectively. In addition, different types of oxygenated groups exhibited various activities based on molecular model tests, following the sequence carboxylic > hydroxyl > carbonyl > ether > aldehyde > edge. Based on the underlying relationship between the oxygenated groups, topological structures, and mechanical strain in the carbon nanoparticles, we speculate that mechanical strain plays a critical role in the formation of oxygenated groups, thereby regulating their photocatalytic activities. The findings in this work provide novel insights into the roles of oxygenated groups and the mechanical strain of carbon nanoparticles in their environmental behavior.
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Affiliation(s)
- Zhe Ding
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China
| | - Wentao Zhang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China
| | - Jianjun Liang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China; Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, China.
| | - Shirong Qiang
- Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, China; Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Wei Wang
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China
| | - Ping Li
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China; Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, China
| | - Qiaohui Fan
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou, 730000, China; Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, China
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9
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Yan W, Chen Y, Han L, Sun K, Song F, Yang Y, Sun H. Pyrogenic dissolved organic matter produced at higher temperature is more photoactive: Insight into molecular changes and reactive oxygen species generation. JOURNAL OF HAZARDOUS MATERIALS 2022; 425:127817. [PMID: 34883369 DOI: 10.1016/j.jhazmat.2021.127817] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/04/2021] [Accepted: 11/14/2021] [Indexed: 06/13/2023]
Abstract
Pyrogenic dissolved organic matter (pyDOM) is the photolabile fraction in the dissolved organic matter pool. However, the molecular changes and reactive oxygen species generation of pyDOMs under continuous irradiation, and how these vary with feedstock type and pyrolysis temperature, are not well understood. In this study, the soluble fractions of 300 and 450 ºC biochars (pyDOM300 and pyDOM450) were subjected to photo-irradiation. PyDOM450 was of higher aromaticity, molecular variety, but lower unsaturation than pyDOM300. The molecular weight, aromaticity, and double bond equivalents of pyDOMs generally decreased after photo-irradiation. The degradation pattern of pyDOMs can be divided into two stages. In the initial 24 h, pyDOM300 degraded faster than pyDOM450, with the more profound transformation of condensed aromatics and carbohydrate into aliphatic/proteins, lignins, and tannins in pyDOM300. After 720 h irradiation, however, the degradation ratio of pyDOM450 (36.2-43.9%) exceeded that of pyDOM300 (23.7-30.3%), with the initially preserved condensed aromatics in pyDOM450 further transforming into aliphatic/proteins and tannins. This was potentially attributed to the generation of more reactive oxygen species (·OH and 1O2) in pyDOM450. This study uncovered the photodegradation mechanisms of pyDOMs at molecular scale and helped to understand their cycling and effects on environment.
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Affiliation(s)
- Wenhui Yan
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Yalan Chen
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Lanfang Han
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Ke Sun
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Fanhao Song
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Yan Yang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Haoran Sun
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
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10
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Chen N, Cao S, Zhang L, Peng X, Wang X, Ai Z, Zhang L. Structural dependent Cr(VI) adsorption and reduction of biochar: hydrochar versus pyrochar. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 783:147084. [PMID: 34088126 DOI: 10.1016/j.scitotenv.2021.147084] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
Hydrochar and pyrochar are two typical biochars, and possess different intrinsic structures and chemical properties as well as pollutant removal abilities. However, their structural dependent pollutant removal performances and the related mechanisms are far less studied. In this study, we systematically compared the Cr(VI) removal processes of hydrochar and pyrochar in dark and under simulated sunlight at pH 5.7 ± 0.1, aiming to clarify the structural dependent Cr(VI) removal of biochar. In dark, hydrochar could remove 19.0% of Cr(VI) only via adsorption within 8 h, less than that (23.5%) of pyrochar via both adsorption and indirect solution •O2- reduction pathway. Although simulated sunlight irradiation could significantly promote the Cr(VI) reduction performances of both hydrochar and pyrochar, the Cr(VI) reduction percentage (88.1%) of hydrochar via both direct surface electron reduction and indirect solution •O2- reduction pathways, was much higher than that (30.2%) of pyrochar only via indirect solution •O2- reduction pathway. This different Cr(VI) reduction pathway of hydrochar and pyrochar was arisen from their structural dependent Cr(VI) adsorption models, as revealed by ATR-FTIR characterization and DFT calculation. More phenolic -OH group on hydrochar surface provided abundant sites for Cr(VI) chemical adsorption to form a strong inner-sphere complex, favoring the interfacial electron transfer for the direct surface Cr(VI) reduction. In contrast, more micropores in pyrochar were responsible for the Cr(VI) physical adsorption via intra-particle and boundary layer diffusion, which hampered the surface Cr(VI) direct reduction because of the weak interfacial interaction between Cr(VI) and pyrochar. This study clarifies the influence of surface structure on the Cr(VI) adsorption and reduction pathways of biochar, and also provides an efficient Cr(VI) removal strategy with sunlight and hydrochar.
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Affiliation(s)
- Na Chen
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Shiyu Cao
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Lin Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Xing Peng
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Xiaobing Wang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Zhihui Ai
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Lizhi Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China.
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11
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Lian F, Zhang Y, Gu S, Han Y, Cao X, Wang Z, Xing B. Photochemical Transformation and Catalytic Activity of Dissolved Black Nitrogen Released from Environmental Black Carbon. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:6476-6484. [PMID: 33844909 DOI: 10.1021/acs.est.1c00392] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Biomass combustion results in the formation and wide distribution of black carbon (BC) in soils, wherein the dissolved fractions are among the most active components. Although the presence of dissolved black nitrogen (DBN) in BC has been identified, its environmental behavior and implication are not understood. This study investigated the photochemical transformation and catalytic activity of DBN under simulated solar irradiation. DBN is more easily transformed than dissolved BC due to its photoactive heteroaromatic N structure, and the half-life of DBN produced at 500 °C (8.6 h) is two times shorter than that of the dissolved BC counterpart (23 h). Meanwhile, solar irradiation is favorable for the homoaggregation of DBN. During irradiation, DBN generates not only reactive oxygen species (e.g., 1O2, O2-, and •OH) but also reactive nitrogen species (mainly •ON), which account for its higher photocatalytic degradation of bisphenol A than dissolved BC. These findings shed new light on the impact of heteroatoms on the phototransformation and activity of BC as well as cycling of N in terrestrial systems.
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Affiliation(s)
- Fei Lian
- Institute of Environmental Processes and Pollution Control, and School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Yikang Zhang
- Institute of Environmental Processes and Pollution Control, and School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Shiguo Gu
- Institute of Environmental Processes and Pollution Control, and School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Yaru Han
- Institute of Environmental Processes and Pollution Control, and School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Xuesong Cao
- Institute of Environmental Processes and Pollution Control, and School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Zhenyu Wang
- Institute of Environmental Processes and Pollution Control, and School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States
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12
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Sun X, Guo P, Sun Y, Cui Y. Adsorption of Hexavalent Chromium by Sodium Alginate Fiber Biochar Loaded with Lanthanum. MATERIALS 2021; 14:ma14092224. [PMID: 33925966 PMCID: PMC8123644 DOI: 10.3390/ma14092224] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/05/2021] [Accepted: 04/20/2021] [Indexed: 11/16/2022]
Abstract
Lanthanun oxide (La2O3) is a lanthanum chemical compound incorporates a sensible anionic complexing ability; however, it lacks stability at a low pH scale. Biochar fibers will give the benefit of their massive space and plethoric uses on the surface to support a metal chemical compound. Herein, wet spinning technology was used to load La3+ onto sodium alginate fiber, and to convert La3+ into La2O3 through carbonization. The La2O3-modified biochar (La-BC) fiber was characterized by SEM, XRD and XPS, etc. An adsorption experiment proved that La-BC showed an excellent adsorption capacity for chromates, and its saturation adsorption capacity was about 104.9 mg/g. The information suggested that the adsorption was in step with both the Langmuir and Freundlich models, following pseudo-second-order surface assimilation mechanics, which showed that the Cr (VI) adsorption was characterized by single-phase and polyphase adsorption, mainly chemical adsorption. The thermodynamic parameters proved that the adsorption process was spontaneous and endothermic. The mechanistic investigation revealed that the mechanism of the adsorption of Cr (VI) by La-BC may include electrostatic interaction, ligand exchange, or complexation. Moreover, the co-existing anions and regeneration experiments proved that the La-BC is recyclable and has good prospects in the field of chrome-containing wastewater removal.
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Affiliation(s)
- Xinzhe Sun
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China;
| | - Peng Guo
- School of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China;
| | - Yuanyuan Sun
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China;
- Correspondence: (Y.S.); (Y.C.); Tel.: +86-152-6423-0805 (Y.S.); +86-137-9323-5399 (Y.C.)
| | - Yuqian Cui
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China;
- Correspondence: (Y.S.); (Y.C.); Tel.: +86-152-6423-0805 (Y.S.); +86-137-9323-5399 (Y.C.)
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13
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Yi K, Lei M, Peng L, Chen A, Luo S. Sunlight-driven degradation of diethyl phthalate via magnetically modified biochar catalysts in water: Internal electron transfer mechanism. CHEMOSPHERE 2021; 269:129366. [PMID: 33385662 DOI: 10.1016/j.chemosphere.2020.129366] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/13/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
This study presents a one-step synthetic approach for magnetic biochar (MBC) photo-degradation of diethyl phthalate (DEP). The results showed that MBC exhibited better catalytic property for DEP degradation than BC, and its catalytic performance was influenced by the amount of Fe doping. Electron paramagnetic resonance (EPR), quenching experiments, and chemical probe studies confirmed the presence of persistent free radicals (PFRs), hydroxyl radicals (·OH), and superoxide anion radical (·O2-) in both of BC and MBC. Solar light promoted the formation of PFRs in BC system, which transferred electrons to oxygen to form ·O2-, thus yielding ·OH. On the other hand, electron transfer occurred between PFRs and Fe3+ for MBC, Fe2+ played an important role in activation of O2 and ·O2- production. Subsequently, photo-Fenton reaction was primarily responsible for ·OH formation. This work compared the different generation pathways for ROS between BC and MBC and provides new insight into the possible mediatory roles of BC in O2 activation under solar light by transition metals.
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Affiliation(s)
- Kexin Yi
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, PR China; College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, PR China
| | - Ming Lei
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, PR China
| | - Liang Peng
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, PR China
| | - Anwei Chen
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, PR China
| | - Si Luo
- College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, PR China.
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14
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Li L, Wang X, Fu H, Qu X, Chen J, Tao S, Zhu D. Dissolved Black Carbon Facilitates Photoreduction of Hg(II) to Hg(0) and Reduces Mercury Uptake by Lettuce ( Lactuca sativa L.). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11137-11145. [PMID: 32804493 DOI: 10.1021/acs.est.0c01132] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Here, we investigated the photoreduction of Hg(II) (Hg(NO3)2) mediated by dissolved black carbon (DBC, <0.45 μm size fraction) collected from water extracts of biochar derived by pyrolyzing crop residues (rice, soybean, and peanut). Under simulated sunlight conditions, the presence of 5 mg C/L DBC significantly facilitated the production of Hg(0) from Hg(II) (initially at 10 nmol/L) with a reduction ratio of 73 ± 4% in 5.3 h. Inhibition of photolysis-induced reactive oxygen species by a quencher or removal of dissolved oxygen indicated that Hg(II) was mainly reduced by superoxide anion (O2•-). Reduction by electrons transferred from photoexcited DBC components or by organic free radicals produced from photo-Fenton-like reactions was also proposed to play a role. Contrary to dissolved humic substances, the DBC-mediated photoreduction of Hg(II) led to unique positive mass-independent isotopic fractionation (MIF) of Hg(0) (Δ199Hg = 1.8 ± 0.3‰), which was attributed to the dominance of secondary Hg(II) reduction by O2•-. The leachate from soil amended with rice biochar at 1-5% mass ratios exhibited significantly higher photocatalytic efficiency than that from unamended soil (wherein the reduced Hg(0) increased from 27 ± 1 to 63 ± 2% in maximum), and the efficiency positively correlated with the percentage of amended biochar. Under natural illumination conditions, the total mercury and/or methylmercury uptake by roots, shoots, and leaves of lettuce (Lactuca sativa L.) grown in water extracts of rice biochar-amended soil was consistently lower (up to 70 ± 20%) than that without the biochar amendment. The findings highlight that DBC might play an important and previously unrecognized role in the biogeochemical cycle and the environmental impact of mercury.
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Affiliation(s)
- Langlang Li
- School of Urban and Environmental Sciences, Key Laboratory of the Ministry of Education for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Xuejun Wang
- School of Urban and Environmental Sciences, Key Laboratory of the Ministry of Education for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Heyun Fu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210046, China
| | - Xiaolei Qu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210046, China
| | - Jiubin Chen
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
| | - Shu Tao
- School of Urban and Environmental Sciences, Key Laboratory of the Ministry of Education for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Dongqiang Zhu
- School of Urban and Environmental Sciences, Key Laboratory of the Ministry of Education for Earth Surface Processes, Peking University, Beijing 100871, China
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15
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Shi H, Wang M, Wang B, Huang Q, Gao S. Insights on photochemical activities of organic components and minerals in dissolved state biochar in the degradation of atorvastatin in aqueous solution. JOURNAL OF HAZARDOUS MATERIALS 2020; 392:122277. [PMID: 32086092 DOI: 10.1016/j.jhazmat.2020.122277] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 02/08/2020] [Accepted: 02/10/2020] [Indexed: 06/10/2023]
Abstract
This study systematically investigated the photocatalytic activity of dissolved state biochar (DSB) with different pyrolysis temperature to the degradation of atorvastatin (ATV), a medicine widely used to combat hyperlipidemia. It was found that the photocatalytic efficiency of DSB increased with the decrease of pyrolysis temperature, that is, DSB300 (DSB with 300 °C of pyrolysis temperature) had the greatest photocatalytic activity in same condition, which was attributed to the dual role of DSB300 as heterogeneous photocatalyst and photosensitizer. The mineral components were responsible for the heterogeneous photocatalytic activity of DSB300. Organic carbon components could synergistically enhance the heterogeneous photocatalytic activity by enhancement of electron-hole separation, and contribute to the formation of singlet oxygen (1O2) and triplet-excited state (3DSB*) as well. The identification of intermediate products and X-ray photoelectron spectroscopy (XPS) analysis of irradiated DSB300/ATV revealed that cross-coupling reaction between ATV and DSB existed in the photodegradation process of ATV. The detailed photodegradation pathways of ATV were proposed, which was triggered by oxygen insertion of pyrrole ring and hydroxyl addition. Meanwhile, the modification of DSB300 under irradiation was evidently attenuated with ATV as shown by multiple characterizations, which helped to keep the stability of DSB300 in photochemical reaction process.
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Affiliation(s)
- Huanhuan Shi
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Mengjie Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Beibei Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, PR China
| | - Qingguo Huang
- College of Agricultural and Environmental Sciences, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA, 30223, United States
| | - Shixiang Gao
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China.
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16
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Zhang B, Zhou S, Zhou L, Wen J, Yuan Y. Pyrolysis temperature-dependent electron transfer capacities of dissolved organic matters derived from wheat straw biochar. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 696:133895. [PMID: 31465929 DOI: 10.1016/j.scitotenv.2019.133895] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/29/2019] [Accepted: 08/11/2019] [Indexed: 05/22/2023]
Abstract
Dissolved organic carbons in biochar (BDOM), obtained from thermal treatment (i.e., pyrolysis) of biomass, is of great importance due to their excellent redox properties and capacity to remove contaminants from the aqueous and soil environment. However, little is known about the intimate relationship between redox activity of BDOM and pyrolysis temperatures of the biomass. In this study, BDOMs were extracted from wheat straw biochar at different temperatures (from 300 °C to 700 °C). The physicochemical analyses indicated that the quinone and aromatic moieties in BDOM increased with the increase in pyrolysis temperature up to 500 °C, and then decreased as the temperature continued to rise. The results of electrochemical analysis revealed that the electron transfer capability (ETC) reached a maximum for the BDOM-500 with an electron donor capability (EDC) of 0.14 mmole- (g C)-1 and electron accepting capability (EAC) of 0.31 mmole- (g C)-1, which were both significantly higher than that of other as-prepared BDOMs. The EAC and EDC of BDOM samples both followed the order BDOM-500 > BDOM-400 > BDOM-600 > BDOM-300 > BDOM-700, demonstrating that the quinone and aromatic groups highly contributed to the redox activity of the BDOM. For Cr(VI) removal, the highest removal efficiency (~77%) was achieved in the presence of BDOM-500 and lactate as an electron donor, which was consistent with the profiles of ETC. These findings present a guidance for the optimization of BDOM that efficiently mediates pollutants removal for environmental remediation.
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Affiliation(s)
- Beiping Zhang
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Shaofeng Zhou
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Lihua Zhou
- Institute of Natural Medicine & Green Chemistry, School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Junlin Wen
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Yong Yuan
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.
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