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Tafese BN, Ganesh T, Solomon A, Sundararaju B, Garg N, Alebachew B. Efficient Adsorptive Removal of Methylene Blue Dye from Aqueous Solution Using Eragrostis Teff Biomass-Derived Nitrogen and Phosphorus-Codoped Carbon Quantum Dots. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:72-83. [PMID: 38147594 DOI: 10.1021/acs.langmuir.3c01813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Carbon quantum dots have a great application potential in environmental protection via adsorption technology due to their large specific surface area and negative zeta potential. In this work, nitrogen and phosphorus-codoped carbon quantum dots (NP-CQDs) with a large specific surface area and negative zeta potential were successfully synthesized by a single-step hydrothermal synthesis. Batch adsorption studies were utilized to assess the adsorbent's capacity to remove common methylene blue (MB) dye contaminants from an aqueous solution. The experiment showed that MB dye could be removed in 30 min under optimum experimental conditions, with a removal efficiency of 93.73%. The adsorbent's large surface area of 526.063 m2/g and negative zeta potential of -12.3 mV contribute to the high removal efficiency. The Freundlich isotherm model fits the adsorption process well at 298 K, with R2 and n values of 0.99678 and 4.564, respectively, indicating its applicability. A kinetic study demonstrated that the pseudo-second-order model, rather than the pseudo-first-order model, is more suited to represent the process of MB dye adsorption onto NP-CQDs. This research established a simple and cost-effective method for developing a highly efficient NP-CQD adsorbent for organic dye degradation by adsorption.
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Affiliation(s)
- Bisrat Nigusie Tafese
- Department of Materials Science and Engineering, School of Mechanical, Chemical, and Materials Engineering (SoMCME), Adama Science and Technology University (ASTU), P.O. Box 1888, Adama 1888, Ethiopia
| | - Thothadri Ganesh
- Department of Materials Science and Engineering, School of Mechanical, Chemical, and Materials Engineering (SoMCME), Adama Science and Technology University (ASTU), P.O. Box 1888, Adama 1888, Ethiopia
| | - Abraham Solomon
- Department of Materials Science and Engineering, School of Mechanical, Chemical, and Materials Engineering (SoMCME), Adama Science and Technology University (ASTU), P.O. Box 1888, Adama 1888, Ethiopia
| | - Basker Sundararaju
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208 016, India
| | - Nidhi Garg
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208 016, India
| | - Biruk Alebachew
- Department of Soft Matter Physics, University of Potsdam, Am Neuen Palais 10, Potsdam 14469, Germany
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Zhou T, Hu J, Liu T, Zhao F, Yin Y, Guo M. Engineering Characteristics and Microscopic Mechanism of Soil-Cement-Bentonite (SCB) Cut-Off Wall Backfills with a Fixed Fluidity. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4971. [PMID: 37512245 PMCID: PMC10381425 DOI: 10.3390/ma16144971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/07/2023] [Accepted: 07/08/2023] [Indexed: 07/30/2023]
Abstract
Soil-cement-bentonite (SCB) backfill has been widely used in constructing cut-off walls to inhibit groundwater movement in contaminated sites. This study prepares SCB backfill with fixed fluidity. We conducted a series of experiments to investigate the engineering characteristics and microscopic mechanism of the backfill. The results indicate that the water content in the slurry was more sensitive to the bentonite content. The unconfined compression strength (UCS) value increased with an increase in the cement content, and the change with an increase in bentonite content was not noticeable. The permeability coefficient decreased distinctly with an increase in the cement and bentonite contents. The porosity of the SCB backfill increased with increasing bentonite content and decreased with increasing cement content. The UCS of SCB backfill was linearly and negatively correlated with the porosity; the permeability coefficient was not significantly related to the porosity. The percentage of micro- and small-pore throats in the backfill increased with increasing bentonite and cement contents. As cement and bentonite content increased by 6% in the backfill, the proportion of micro- and small-pore throats increased by 0.7% and 1.2%, respectively. The percentage of micro- and small-pore throats is deduced to be more suitable as a characterization parameter for the permeability of the SCB backfill. The overall results of this study show that the reasonably proportioned SCB backfill has potential as an eco-friendly and cost-effective material. Based on the requirements of strength and permeability coefficient (UCS > 100 kPa, 28 days permeability coefficient <1 × 10-7 cm/s), we suggested using a backfill with 12% bentonite and 9% cement as the cut-off wall mix ratio.
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Affiliation(s)
- Tan Zhou
- School of Resources and Safety Engineering, Central South University, Changsha 410083, China
| | - Jianhua Hu
- Zijin School of Geology and Mining, Fuzhou University, Fuzhou 350108, China
| | - Taoying Liu
- School of Resources and Safety Engineering, Central South University, Changsha 410083, China
| | - Fengwen Zhao
- School of Resources and Safety Engineering, Central South University, Changsha 410083, China
| | - Yanjun Yin
- School of Resources and Safety Engineering, Central South University, Changsha 410083, China
| | - Mengmeng Guo
- School of Resources and Safety Engineering, Central South University, Changsha 410083, China
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Rehman S, Yousaf S, Ye Q, Chenhui L, Bilal M, Shaikh AJ, Khan MS, Shahzad SA, Wu P. Bentonite binding with mercury(II) ion through promotion of reactive oxygen species derived from manure-based dissolved organic matter. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:26107-26119. [PMID: 36352071 DOI: 10.1007/s11356-022-23948-z] [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: 07/27/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
This study reports the mercury binding by bentonite clay influenced by cattle manure-derived dissolved organic matter (DOM). The DOM (as total organic carbon; TOC) was reacted with bentonite at 5.2 pH to monitor the subsequent uptake of Hg2+ for 5 days. The binding kinetics of Hg2+ to the resulting composite was studied (metal = 350 µM/L, pH 5.2). Bentonite-DOM bound much more Hg2+ than original bentonite and accredited to the establishment of further binding sites. On the other hand, the presence of DOM was found to decrease the Hg2+ binding on the clay surface, specifically, the percent decrease of metal with increasing DOM concentration. Post to binding of DOM with bentonite resulted in increased particle size diameter (~ 33.37- ~ 87.67 nm) by inducing the mineral modification of the pore size distribution, thus increasing the binding sites. The XPS and FTIR results confirm the pronounced physico-chemical features of bentonite-DOM more than that of bentonite. Hydroxyl and oxygen vacancies on the surface were found actively involved in Hg2+ uptake by bentonite-DOM composite. Furthermore, DOM increased the content of Hg2+ binding by ~ 10% (pseudo-second-order qe = 90.9-100.0) through boosting up Fe3+ reduction with the DOM. The quenching experiment revealed that more oxygen functionalities were generated in bentonite-DOM, where hydroxyl was found to be dominant specie for Hg2+ binding. The findings of this study can be used as theoretical reference for mineral metal interaction under inhibitory or facilitating role of DOM, risk assessment, management, and mobilization/immobilization of mercury in organic matter-containing environment.
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Affiliation(s)
- Saeed Rehman
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China
| | - Sayyaf Yousaf
- Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad Campus, KPK, University Road, Abbottabad, 22060, Pakistan
| | - Quanyun Ye
- 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
| | - Liu Chenhui
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China
| | - Muhammad Bilal
- Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad Campus, KPK, University Road, Abbottabad, 22060, Pakistan
| | - Ahson Jabbar Shaikh
- Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, KPK, University Road, Abbottabad, 22060, Pakistan
| | - Muhammad Saqib Khan
- Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad Campus, KPK, University Road, Abbottabad, 22060, Pakistan
| | - Sohail Anjum Shahzad
- Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, KPK, University Road, Abbottabad, 22060, Pakistan
| | - Pingxiao Wu
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China.
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, 510006, People's Republic of China.
- Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou, 510006, People's Republic of China.
- Guangdong Engineering and Technology Research Center for Environmental Nanomaterials, Guangzhou, 510006, People's Republic of China.
- Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal, Guangzhou, 510006, People's Republic of China.
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