Desalination and Water Treatment
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2014
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IF 0.987
Ruihua Huang,Bo Wang,Bingchao Yang,Dongsheng Zheng,Zengqiang Zhang
An adsorbent was prepared from bentonite modified by hexadecyltrimethylammonium bromide (HDTMAB) and N-2-hydroxypropyl trimethyl ammonium chloride chitosan (HTCC). This adsorbent was named as HDTMAB–HTCC bentonite. It would be used for the simultaneous adsorption of phenol and Cr(VI) from aqueous solution. By the method of single-factor experiment, the optimum preparation conditions of HDTMAB–HTCC bentonite were obtained. For bentonite (5 g), 1.0 g HDTMAB and 0.5 g HTCC were adopted as the modifying reagents. The reaction was carried out for 2 h at 80°C. The removals towards phenol and Cr(VI) enhanced with the increase in the amount of adsorbent dosage. The relatively high removals towards phenol and Cr(VI) occurred at a pH value of 1.5 or so. During the simultaneous adsorption process of phenol and Cr(VI), phenol was adsorbed by the partition from the organic phase formed by HDTMAB, while Cr(VI) was mostly adsorbed by the electrostatic interactions between HTCC and Cr(VI). No direct competition was observed due to different adsorption sites.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2023
·
IF 8.7
Haijian Xie,Jiawei Wu,Mengzhen Yu,Huaxiang Yan,Shakil Masum,Peifu Cai,Yun Chen
Bisphenol A (BPA) is a toxic endocrine disruptor often found in landfill leachate . Adsorption behaviors and mechanisms of BPA onto organo-bentonites amended loess , e.g., Hexadecyltrimethylammonium chloride-bentonite (HTMAC-B) and Carboxymethylcellulose-bentonite (CMC-B) were experimentally investigated. The adsorption capacity of loess amended by HTMAC-B (LHB) and CMC-B (LCB) is 4.2 and 4 times greater than that of loess (L), respectively. It is attributed to the increase of hydrogen bonds and hydrophobic lateral interactions between the adsorbent and the adsorbate. The binary (Pb 2+ -BPA) systems may enhance BPA adsorption onto the samples by the formation of coordination bonds between the hydroxyl group of BPA and Pb 2+ ions. A cycled column test was used for investigating the transport behavior of BPA in LHB and LCB samples. The hydraulic conductivity of loess amended by the organo-bentonite (e.g., HTMAC-B, CMC-B) is generally lower than 1 × 10 −9 m/s. Especially for CMC-B amended loess, the hydraulic conductivity can be reduced to 1 × 10 −12 m/s. This guarantees the hydraulic performance of the liner system. Transport behavior of BPA in cycled column test is explained by the mobile-immobile model (MIM). Modelling results showed that loess amended by organo-bentonites can increase the breakthrough time of BPA. In comparison to loess-based liner, the breakthrough time of BPA for LHB and LCB can be increased by a factor of 10.4 and 7.5, respectively. These results indicate that organo-bentonites can serve as a potentially effective amendment for improving the adsorption of loess-based liners.
研究领域:
环境科学
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土壤学
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产品关联
DOI
PubMed
高影响因子
Materials
·
2023
·Vol. 16
·期 3
·1255
·
IF 3.4
Haijie He,Tao Wu,Xiaole Shu,Kuan Chai,Zhanhong Qiu,Shifang Wang,Jun Yao
Adding organically modified bentonite into impervious wall materials may improve the adsorption of organic pollutants. In this study, cetyltrimethylammonium bromide organically modified bentonite (CTMAB bentonite) was mixed with sodium bentonite and kaolin to obtain two materials, which were then used as cut-off walls for typical pollutants. Soil column consolidation tests, diffusion tests, and breakdown tests were conducted to study migration of organic pollutants in soil columns. The parameter sensitivity of pollutant transport in the cut-off wall was analysed by numerical simulation. The sodium bentonite mixed with 10% CTMAB bentonite and kaolin-CTMAB bentonite showed the greatest impermeability: with a consolidation pressure of 200 kPa, the permeability coefficients were 1.03 × 10−8m/s and 3.49 × 10−9m/s, respectively. The quantity of phenol adsorbed on sodium bentonite-CTMAB bentonite increased with increasing water head height. The kaolin-CTMAB bentonite column showed the best rhodamine B adsorption performance, and the adsorption rate reached 98.9% on day 67. The numerical results showed that the permeability coefficient was positively correlated with the diffusion of pollutants in the soil column. The quantity adsorbed on the soil column was positively correlated with the retardation factor, and the extent of pollutant diffusion was negatively correlated with the retardation factor. This study provides a technical means for the optimal design of organic pollutant cut-off walls.Keywords:organic pollutants;organic bentonite;soil column;numerical simulation;kaolin
研究领域:
环境科学
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土壤学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2022
·
IF 2.042
Chengzhang Cao,Yuhuan Bu,Leiju Tian,Laiju Han
Compared with cement stone, epoxy resin has a higher compressive strength, lower elastic modulus, and better seepage capacity in repairing cement sheath or cementing in special formations. The viscosity of epoxy resin is significantly affected by temperature, which causes a serious decrease in the settlement stability. In this study, the effects of the diluent, solid epoxy resin and rheological agents on the slurry viscosity, and settlement stability were evaluated. The results indicate that fumed silica and organic bentonite have a good effect on improving the settlement stability, but have negative effects on pumpability. Therefore, a method to improve the settlement stability of epoxy resin-based cementing slurry was developed. Fumed silica and organic bentonite were compounded to increase the settlement stability and lower dosage (fumed silica less than 3 wt.%) can avoid too much negative effect on pumpability. Viscosity tests showed that diluent work more effectively at low temperatures while solid ER and Xanthan gum are more effective at high temperatures. When they use together, the viscosity at 90 °C is increased by 33% while decrease by 86% at 25 °C. When the temperature increases downhole, the viscosity of diluent is closed to ER, and tackifying materials dominate, increasing the viscosity at high temperatures. Based on the method proposed in this paper, the epoxy resin-based cementing slurry can increase the settlement stability to less than 0.01 g/cm3 when the slurry density is less than 1.3 g/cm3 and a settlement stability of less than g/cm3 when slurry density is less than 1.59 g/cm3 .
研究领域:
石油工程
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材料科学
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产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 25
·期 22
·21693-21700
·
IF 2.8
Luan Ling-Yu,Zhang Li,Wang Li-Hong
Synthesized organobentonite (SOB), montmorillonite (MMT), and commercial organobentonite (COB) were used as adsorbents for paraffin oil, a model pollutant in land-based oil spills and oil pipeline rupture. The characterization of clays was carried out with scanning electron microscopy (SEM), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). After adsorption, oil was separated from adsorbents with a carbon dioxide responsive solvent N,N-dimethylcyclohexylamine (DMCHA), and DMCHA was subsequently separated from paraffin oil upon CO 2 bubbling instead of distillation with high energy cost. The adsorption capacity of oil to SOB, MMT, and COB was 0.686, 1.124, and 1.239 g/g, respectively. It was found that the adsorption capacity and rinsed amount of the adsorbents depended on the d-spacing, which is related to surfactant content. Electrical conductivity and pH measurements suggested that the separation process occurred via two steps. Firstly, during the initial 35 min, carbonate ions coexisted with bicarbonate ions. Then, only bicarbonate ions existed after the introduction of CO 2 gas for 120 min. Thus, organobentonites were feasible for hydrocarbon adsorption and could be simply reused by an amine-based responsive solvent. This work provided a cost-effective and sustainable method of recycling of organobentonites and the responsive solvent, which can be used to deal with leaked oil and oil spills.
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Wenhao Wu,Yuan Lan,Yaxiong Zeng,Daohui Lin,Kun Yang
Organobentonites, i.e., bentonites coated with surfactants such as cetyltrimethylammonium (CTAB), are superior and low-cost sorbents for removal of organic contaminants from wastewater. Nonlinear sorption of polar organic compounds such as phenols and anilines by organobentonites were widely observed and interpreted by adsorption mechanism. However, in this study, it was observed that the nonlinear sorption of phenols and anilines by CTAB coated bentonites (CTAB-bentonites) should be attributed to nonlinear partition mechanism with the additional space limitation in CTAB-bentonites for nonlinear partitioning, rather than adsorption mechanism. This nonlinear partition mechanism is supported by that (i) organobentonites is a partition medium, identified by the linear isotherms of polycyclic aromatic hydrocarbons (PAHs) and nitrobenzenes ; (ii) sorption coefficients (log K d ), the ratio of adsorbed amount ( q e ) to equilibrium concentration ( C e ), and Dubinin-Ashtakhov (DA) model fitted sorption capacity (log Q 0 ) of organic compounds, by a given CTAB-bentonite, are positively correlated with their octanol-water distribution coefficients (log K OW ) and solubility in octanol (log S o ) respectively; (iii) log K d and log Q 0 of a given organic compound by CTAB-bentonites are positively correlated with organic carbon contents ( f oc ) of CTAB-bentonites, but not specific surface area. Specific interaction (i.e., hydrogen-bonding interaction), in addition to van der Waals force , is responsible for the nonlinear partitioning of phenols and anilines into CTAB-bentonites, because of the positively linear relationship between DA model fitted sorption affinity ( E ) and hydrogen-bonding donor parameter ( α m ) of organic compounds. These results could help the recognizing of the nonlinear sorption behaviors of organic compounds by organobentonites and promote their environmental applications in wastewater treatment .
研究领域:
环境科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
Separations
·
2023
·Vol. 10
·期 10
·523
·
IF 2.6
Xiangfen Cui,Jingmei Liao,Huaying Liu,Wei Tang,Cheng Tie,Senlin Tian,Yingjie Li
The presence of organic pollutants in wastewater remains a prominent environmental concern due to the related ecological and health hazards. In response, this study employs an adsorptive methodology to address the removal of phenol and catechol, utilizing an organo-bentonite material modified with a pH-responsive switchable surfactant, dodecyldimethylamine oxide (C12DAO). The synthesized organo-bentonite (C12DAO-Bt) manifests commendable thermostability resulting from thermogravimetric analyses. The adsorption capacities of C12DAO-Bt concerning phenol and catechol intensify with the augmentation of the C12DAO/bentonite mass ratio. The utmost adsorption capacities of 150C12DAO-Bt, deduced through a pseudo-second-order kinetic model, stand at 5.72 mg·g−1for phenol and 5.55 mg·g−1for catechol, respectively. Subject to modification by a pH-responsive surfactant, conditions leaning towards weakly acidic and neutral conditions (pH = 6~7) are conducive to the adsorption of phenolic compounds. Conversely, alkaline conditions (pH = 8~9) facilitate the dissociation of adsorbates from adsorbents. The augmentation of cationic strength within the examined scope incites the adsorption procedure while impeding the desorption efficacy. In the case of cationic species with comparable ionic strengths, Na+exhibited a superior effect on the adsorption–desorption dynamics of phenol, while Ca2+exerts a more pronounced effect on those of catechol. Moreover, even following five consecutive acid–base regulation cycles, C12DAO-Bt retains a relatively high adsorption capacity and desorption efficacy, which underscores its exceptional regenerative capacity for removing phenolic compounds from wastewater.Keywords:pH-responsive surfactants;organic bentonite;reversible adsorption;phenolic pollutants;wastewater
研究领域:
环境科学
·
化学工程
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产品关联
DOI
高影响因子
Scientific Reports
·
2017
·Vol. 7
·期 1
·1-10
·
IF 4.259
Liu Yao,Zhu Lizhong
Organobentonite has been successfully applied in industrial wastewater treatment. However, the solid-liquid separation in wastewater treatment still needs improvement. This study presents an enhanced approach with high removal efficiency and short separation time for dispersed dye-production wastewater using self-assembled organobentonite in a one-step process with poly-aluminium chloride (PAC). The enhanced effects of PAC on wastewater treatment by organobentonite were comprehensively evaluated. Following the primary decontamination by the self-assembled organobentonite, the removal efficiency for dispersed dye-production wastewater was strengthened with PAC coagulation. The removal rates of TOC and organic pollutants were 55.0% and 63.5%, respectively, with the PAC-enhanced approach and were 1.3- and 1.6-fold higher, respectively, than those with the self-assembled organobentonite approach. The combination of PAC with self-assembled organobentonite was able to break the stability of the organobentonite suspension and enlarge the floc size, and thus reduce the solid-liquid separation time from 30 min to 10 min. Additionally, this enhanced approach could improve the biodegradability of wastewater with the BOD 5 /COD Cr ratio increasing from 0.22 to 0.39, which was 4.1-fold higher than that of only organobentonite in a one-step process. Therefore, the PAC-enhanced approach could be a promising technology for wastewater pretreatment in practical industrial applications.
研究领域:
环境科学
·
水处理工程
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DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
·
2017
·
IF 5.099
Shuai Liu,Pingxiao Wu,Meiqing Chen,Langfeng Yu,Chunxi Kang,Nengwu Zhu,Zhi Dang
Three novel organic vermiculites (VER) modified by amphoteric surfactants (BS, SB and PBS) with different negatively charged groups (carboxylate, sulfonate and phosphate) were demonstrated and used for removal of bisphenol A (BPA) and tetrabromobisphenol A (TBBPA). The difference in the structure and surface properties of modified vermiculites were investigated using a series of characterization methods. BS and SB surfactant mainly adsorbed on the surface and hard to intercalate into the interlayer of VER, while both adsorption and intercalation occurred in PBS modification. This difference resulted in different packing density of surfactant and hydrophobicity according to the results of contact angle, and affect the adsorption capacities ultimately. The adsorption of two pollutants onto these modified vermiculites were very fast and well fitted with pseudo-second-order kinetic model and Langmuir isotherm . PBS-VER exhibited the highest adsorption capacity (92.67 and 88.87 mg g −1 for BPA and TBBPA, respectively) than other two modified vermiculites in this order PBS-VER > BS-VER > SB-VER. The ionic strength (Na + , Ca 2+ ) and coexisting compounds (Pb 2+ , humic acid) have different effects on the adsorption. PBS-VER had a good reusability and could remove ionic (methylene blue and orange G) and molecular (BPA) pollutants simultaneously and effectively due to the function of amphoteric hydrophilic groups and alkyl chains. The results might provide novel information for developing low-cost and effective adsorbents for removal of neutral and charged organic pollutants .
研究领域:
环境科学
·
吸附材料
·
污染控制
·
环境化学
·
功能材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）