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Gan M, Zhou Y, Huang D, He P, Tang B, Cai Y, Zhu J. The enhanced effect of key microorganisms in chromium contaminated soil in Cr(VI) reduction. CHEMOSPHERE 2024; 362:142682. [PMID: 38914286 DOI: 10.1016/j.chemosphere.2024.142682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 06/10/2024] [Accepted: 06/20/2024] [Indexed: 06/26/2024]
Abstract
The escalating threat of Cr(VI) pollution to the environment and human health can be effectively controlled through microbial methods, which are promising, safe, and ecofriendly. To enhance Cr(VI) removal efficiency, scholars have been optimizing strains. However, synergies between in-situ soil particles and crucial microorganisms in soil have rarely been investigated. In this study, Cr(VI) was removed by collaborating with in-situ soil particles and key microorganisms in the soil. The results indicated that within 48 hours, the removal rate of Cr(VI) reached over 99% in the soils+microflora system, which was 45% higher than that of the microflora system alone. Factors such as Cr(VI) concentration, soil dosage, pH level, oxygen availability, and electron donors influenced the removal efficiency of Cr(VI) in the soils+microflora system. The cyclic experiments showed that soil particles effectively prevented chromium invasion on microflora, promoting the growth of crucial microorganisms. The addition of microflora can effectively regulate the composition of soil flora and enhance the efficiency of chromium reduction. Moreover, two strains each of Ochrobactrum sp. and Paenarthrobacter sp., exhibiting remarkable tolerance to Cr(VI), were successfully isolated from these soils, significantly enhancing the reduction capacity of the indigenous microflora towards Cr(VI). Additionally, 16S rRNA-PCR sequence analysis revealed that in-situ soil particles not only synergistically collaborated with the resident microflora for efficient removal of Cr(VI), but also facilitated the proliferation of key microbiota such as Ochrobactrum sp. and Paenarthrobacter sp. Remarkably, when exposed to an initial concentration of 50 mg/L Cr(VI), complete removal was achieved by Paenarthrobacter-2 within a time frame as short as 60 hours. This research found four novel highly efficient strains for reducing Cr(VI) and provides an innovative method for the synergistic interaction between indigenous soil microflora and soil particles to remove heavy metal ions from wastewater.
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Affiliation(s)
- Min Gan
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Yihao Zhou
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Dongli Huang
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Peng He
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Binlin Tang
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Yan Cai
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China
| | - Jianyu Zhu
- School of Minerals Processing and Bioengineering, Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha, 410083, China.
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Cao Y, Guo Q, Miao Z, Tang B, Ma Y, Zhao J, Song H. Cr(VI) removal from contaminated waters using ultra-thin layered meixnerite. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:9725-9737. [PMID: 36063270 DOI: 10.1007/s11356-022-22713-6] [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: 04/23/2022] [Accepted: 08/21/2022] [Indexed: 06/15/2023]
Abstract
Cr(VI) is of great concern to public health and environmental safety due to its high toxicity. Here, we report a low-cost yet highly efficient method to prepare a novel LDH, ultra-thin layered meixnerite, which performed superiorly in treatment of aqueous Cr(VI) with little secondary pollution being induced. The produced ultra-thin layered meixnerite was composed of nanoparticles with a thickness of around 7 nm, less than 9 times the thickness of a single LDH layer. The XRD patterns of the ultra-thin layered meixnerite, in which the characteristic diffraction peaks of a typical LDH were weakened or even disappeared, confirmed the successful delamination. This special morphology of the ultra-thin layered meixnerite was not only helpful to its full dispersion in the Cr(VI)-bearing solutions but also facilitated the formation of more active sorption sites on its external surface. As a result, the maximum sorption capacity of UTLM for Cr(VI) removal was 480.9 mg g-1, far higher than that of OM (196.9 mg g-1). In addition to electrostatic attraction and anion exchange, the ultra-thin layered meixnerite could also become restacked during removal of aqueous Cr(VI) to generate inner-sphere complexation, finally inducing an enhanced Cr(VI) uptake. Furthermore, XPS analysis characterized the promotion of the break of Al-OH bond with the increase in temperature, and the Cr-O peak increased correspondingly from 29.69% at 25 °C to 48.77% at 85 °C, resulting that the ultra-thin layered meixnerite could remove Cr(VI) more effectively at higher reaction temperatures. Therefore, ultra-thin layered meixnerite is very suitable for future application in treatment of industrial wastewaters with elevated temperatures.
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Affiliation(s)
- Yaowu Cao
- State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, 430074, Wuhan, Hubei, People's Republic of China
| | - Qinghai Guo
- State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, 430074, Wuhan, Hubei, People's Republic of China.
| | - Zheyan Miao
- State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, 430074, Wuhan, Hubei, People's Republic of China
| | - Baochun Tang
- Institute of Hydrogeology, Engineering and Environmental Geology Survey of Qinghai Province, Key Laboratory of Hydrogeology and Geothermal Geology of Qinghai Province, 810008, Xining, Qinghai, People's Republic of China
| | - Yuehua Ma
- Institute of Hydrogeology, Engineering and Environmental Geology Survey of Qinghai Province, Key Laboratory of Hydrogeology and Geothermal Geology of Qinghai Province, 810008, Xining, Qinghai, People's Republic of China
| | - Jie Zhao
- State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, 430074, Wuhan, Hubei, People's Republic of China
| | - Hongyu Song
- State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, 430074, Wuhan, Hubei, People's Republic of China
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Inclusion of bimetallic Fe 0.75Cu 0.25-BDC MOFs into Alginate-MoO 3/GO as a novel nanohybrid for adsorptive removal of hexavalent chromium from water. Sci Rep 2022; 12:19108. [PMID: 36351958 PMCID: PMC9646911 DOI: 10.1038/s41598-022-23508-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 11/01/2022] [Indexed: 11/11/2022] Open
Abstract
Metal-organic frameworks (MOFs) as porous materials have recently attracted research works in removal of toxic pollutants from water. Cr(VI) is well-known as one of the most toxic forms of chromium and the selection of efficient and effective Cr(VI)-remediation technology must be focused on a number of important parameters. Therefore, the objective of this work is to fabricate a novel nanohybrid adsorbent for removal of Cr(VI) by using assembled bimetallic MOFs (Fe0.75Cu0.25-BDC)-bound- Alginate-MoO3/Graphene oxide (Alg-MoO3/GO) via simple solvothermal process. The aimed Fe0.75Cu0.25-BDC@Alg-MoO3/GO nanohybrid was confirmed by FTIR, SEM, TEM, XRD and TGA. Adsorptive extraction of Cr(VI) from aqueous solution was aimed by various optimized experimental parameters providing optimum pH = 3, dosage = 5-10 mg, starting concentration of Cr(VI) = 5-15 mg L-1, shaking time = 5-10 min. The point of zero charge (pHPzc) was 3.8. For Cr(VI) removal by Fe0.75Cu0.25-BDC@Alg-MoO3/GO, four isotherm models were estimated: Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) with calculated correlation coefficient (R2 = 0.9934) for Langmuir model which was higher than others. The collected results from the kinetic study clarified that pseudo-second order model is the most convenient one for describing the adsorption behavior of Cr(VI) and therefore, the adsorption process was suggested to rely on a chemisorption mechanism. Thermodynamic parameters referred that the adsorption mechanism is based on a spontaneous and exothermic process. Finally, the emerged Fe0.75Cu0.25-BDC@Alg-MoO3/GO nanohybrid was confirmed as an effective adsorbent for extraction of hexavalent chromium from real water specimens (tap, sea water and wastewater) with percentage recovery values > 98%.
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Li M, Kuang S, Dong J, Ma H, Kang Y. Performance and mechanisms of Cr(VI) removal by nano-MnO2 with different lattices. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Oral O, Yigit A, Kantar C. Role of reactor type on Cr(VI) removal by zero-valent iron in the presence of pyrite: Batch versus sequential batch reactors. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 320:115854. [PMID: 35961140 DOI: 10.1016/j.jenvman.2022.115854] [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: 04/19/2022] [Revised: 07/14/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
This study was conducted to understand the role of application sequence of pyrite and zero-valent iron (Fe0) (simultaneous vs. sequential) on chromium (VI) removal by Fe0. In batch experiments, pyrite and Fe0 were homogeneously mixed in batch reactors maintained at a constant total solids loading of 2 g L-1. In sequential batch experiments, however, the first reactor containing variable doses of pyrite was operated for 20 min, and the liquid fraction from the first reactor was then subsequently loaded into the second reactor containing a fixed Fe0 dose of 1.2 g L-1. The batch reactors achieved much higher Cr(VI) removal efficiency than sequential batch reactors under similar operating conditions due to discrepancies in Fe redox cycling activities between these two systems. In batch reactors, the Fe0 particles deposited on pyrite surface due to electrostatic attraction between negatively charged pyrite and positively charged Fe0, thus, rendering the overall solids surface charge neutral at optimum pyrite and Fe0 doses. As a result, the whole system behaved like a composite material, with pyrite functioning as a support material for Fe0. This stimulated Fe redox cycling more effectively to generate new Fe(II) sites on Fe0 for enhanced Cr(VI) removal relative to Fe0 only system. In sequential batch reactors, however, the Fe redox cycling activity was limited, but significantly increased with increasing pyrite dose in the first reactor. Overall, our results indicate that the stimulatory effect of pyrite on Cr(VI) removal by Fe0 may be much higher if the reactors are operated in batch mode.
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Affiliation(s)
- Ozlem Oral
- Canakkale Onsekiz Mart University, Department of Environmental Engineering, 17100, Canakkale, Turkey.
| | - Aynur Yigit
- Canakkale Onsekiz Mart University, Department of Environmental Engineering, 17100, Canakkale, Turkey
| | - Cetin Kantar
- Canakkale Onsekiz Mart University, Department of Environmental Engineering, 17100, Canakkale, Turkey.
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