Integrated removal of chromium, lead, and cadmium using nano-zero-valent iron-supported biochar: Mechanistic insights and eco-toxicity assessment
The contamination of water and soil by heavy metals (HMs) is a global issue that should be given much more concern. Modified nano-zero-valent iron (nZVI) composites offer an effective strategy for HMs remediation, but few studies have focused on removing coexisting HMs and the eco-toxicity of the co...
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Elsevier
2025-01-01
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| Series: | Ecotoxicology and Environmental Safety |
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| author | Yuzhen Wei Jialu Yu Fasih Ullah Haider Qinhu Zhang Run Chu Cai Liqun |
| author_facet | Yuzhen Wei Jialu Yu Fasih Ullah Haider Qinhu Zhang Run Chu Cai Liqun |
| author_sort | Yuzhen Wei |
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| description | The contamination of water and soil by heavy metals (HMs) is a global issue that should be given much more concern. Modified nano-zero-valent iron (nZVI) composites offer an effective strategy for HMs remediation, but few studies have focused on removing coexisting HMs and the eco-toxicity of the composite. In this study, corn straw biochar-supported nZVI composites (nZVI-BC) were synthesized, characterized and used for the removal of Cr6 +, Pb2+, and Cd2+ in single and multi-system at different composites dosages, metal concentrations, and solution pH. This study indicated that the composites exhibited enhanced removal capacities for Cr6+, Pb2+, and Cd2+ (respectively 82.24, 737.2, and 545.28 mg g−1), which were considerably superior to those observed with the sole application of biochar (0.05, 89.88, and 108.49 mg g−1) and nZVI (39.8, 297.35, and 191.02 mg g−1). Results of the remediation application of the composites to multi-metal systems revealed that intricate interplay existed between coexisting HMs, which hindered the simultaneous removal effect. The coexistence of Cr6+ and Cd2+ decreased both removal efficiencies by 58.16 % and 14.06 % at high Cr6+ levels, respectively, while the coexistence of Cd2+ and Pb2+ resulted in a decrease in Cd2+ removal efficiency by 14.3 %. An in-depth characterization of the underlying adsorption mechanism was performed by using kinetic and isotherms models such as Pseudo-first-order, Pseudo-second-order, Langmuir and Freundlich, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis. Each HM exhibited a distinct adsorption mechanism. The primary removal processes for Cr6+ and Pb2+ involved adsorption, reduction, and precipitation, whereas Cd2+ was mainly removed by adsorption and precipitation. Eco-toxicity experiments revealed that nZVI-BC enhanced pak choi (Brassica rapa L.) seeds germination (13.32, 17.22, and 23.33 %) and vigor indexes (1.22, 1.44, and 1.15) under Cr6+, Pb2+, and Cd2+ contamination, respectively. Nevertheless, an observed shift in toxicity occurred when the composites dosage for Cr6+, Pb2+, and Cd2+ exceeded 2, 4, and 4 g L−1, respectively, thereby instigating adverse effects on the early stages of plant growth. This work elucidates the removal mechanism and intricate reactions between co-existing HMs, highlighting the potential of nZVI-BC as a remediation strategy for HMs contamination. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-3af0bb7325df445d8fdddc440772b5212025-01-23T05:25:51ZengElsevierEcotoxicology and Environmental Safety0147-65132025-01-01289117532Integrated removal of chromium, lead, and cadmium using nano-zero-valent iron-supported biochar: Mechanistic insights and eco-toxicity assessmentYuzhen Wei0Jialu Yu1Fasih Ullah Haider2Qinhu Zhang3Run Chu4Cai Liqun5College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou 730070, PR China; Gansu Provincial Key Laboratory of Arid land Crop Science, Gansu Agricultural University, Lanzhou 730070, PR ChinaCollege of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou 730070, PR China; Gansu Provincial Key Laboratory of Arid land Crop Science, Gansu Agricultural University, Lanzhou 730070, PR ChinaCollege of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou 730070, PR China; Gansu Provincial Key Laboratory of Arid land Crop Science, Gansu Agricultural University, Lanzhou 730070, PR ChinaCollege of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou 730070, PR ChinaCollege of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou 730070, PR ChinaCollege of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou 730070, PR China; Gansu Provincial Key Laboratory of Arid land Crop Science, Gansu Agricultural University, Lanzhou 730070, PR China; Corresponding author at: College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou 730070, PR China.The contamination of water and soil by heavy metals (HMs) is a global issue that should be given much more concern. Modified nano-zero-valent iron (nZVI) composites offer an effective strategy for HMs remediation, but few studies have focused on removing coexisting HMs and the eco-toxicity of the composite. In this study, corn straw biochar-supported nZVI composites (nZVI-BC) were synthesized, characterized and used for the removal of Cr6 +, Pb2+, and Cd2+ in single and multi-system at different composites dosages, metal concentrations, and solution pH. This study indicated that the composites exhibited enhanced removal capacities for Cr6+, Pb2+, and Cd2+ (respectively 82.24, 737.2, and 545.28 mg g−1), which were considerably superior to those observed with the sole application of biochar (0.05, 89.88, and 108.49 mg g−1) and nZVI (39.8, 297.35, and 191.02 mg g−1). Results of the remediation application of the composites to multi-metal systems revealed that intricate interplay existed between coexisting HMs, which hindered the simultaneous removal effect. The coexistence of Cr6+ and Cd2+ decreased both removal efficiencies by 58.16 % and 14.06 % at high Cr6+ levels, respectively, while the coexistence of Cd2+ and Pb2+ resulted in a decrease in Cd2+ removal efficiency by 14.3 %. An in-depth characterization of the underlying adsorption mechanism was performed by using kinetic and isotherms models such as Pseudo-first-order, Pseudo-second-order, Langmuir and Freundlich, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis. Each HM exhibited a distinct adsorption mechanism. The primary removal processes for Cr6+ and Pb2+ involved adsorption, reduction, and precipitation, whereas Cd2+ was mainly removed by adsorption and precipitation. Eco-toxicity experiments revealed that nZVI-BC enhanced pak choi (Brassica rapa L.) seeds germination (13.32, 17.22, and 23.33 %) and vigor indexes (1.22, 1.44, and 1.15) under Cr6+, Pb2+, and Cd2+ contamination, respectively. Nevertheless, an observed shift in toxicity occurred when the composites dosage for Cr6+, Pb2+, and Cd2+ exceeded 2, 4, and 4 g L−1, respectively, thereby instigating adverse effects on the early stages of plant growth. This work elucidates the removal mechanism and intricate reactions between co-existing HMs, highlighting the potential of nZVI-BC as a remediation strategy for HMs contamination.http://www.sciencedirect.com/science/article/pii/S0147651324016087NZVI-BC compositesHeavy metalsRemediationEco-toxicityAdsorption |
| spellingShingle | Yuzhen Wei Jialu Yu Fasih Ullah Haider Qinhu Zhang Run Chu Cai Liqun Integrated removal of chromium, lead, and cadmium using nano-zero-valent iron-supported biochar: Mechanistic insights and eco-toxicity assessment Ecotoxicology and Environmental Safety NZVI-BC composites Heavy metals Remediation Eco-toxicity Adsorption |
| title | Integrated removal of chromium, lead, and cadmium using nano-zero-valent iron-supported biochar: Mechanistic insights and eco-toxicity assessment |
| title_full | Integrated removal of chromium, lead, and cadmium using nano-zero-valent iron-supported biochar: Mechanistic insights and eco-toxicity assessment |
| title_fullStr | Integrated removal of chromium, lead, and cadmium using nano-zero-valent iron-supported biochar: Mechanistic insights and eco-toxicity assessment |
| title_full_unstemmed | Integrated removal of chromium, lead, and cadmium using nano-zero-valent iron-supported biochar: Mechanistic insights and eco-toxicity assessment |
| title_short | Integrated removal of chromium, lead, and cadmium using nano-zero-valent iron-supported biochar: Mechanistic insights and eco-toxicity assessment |
| title_sort | integrated removal of chromium lead and cadmium using nano zero valent iron supported biochar mechanistic insights and eco toxicity assessment |
| topic | NZVI-BC composites Heavy metals Remediation Eco-toxicity Adsorption |
| url | http://www.sciencedirect.com/science/article/pii/S0147651324016087 |
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