Desalination and Water Treatment
·
2024
·
IF 1
Shaojun Li,Xiaoxuan Fan,Zhongping Chen,Lei Bai
A nanosized zeolitic imidazolate framework-67 (ZIF-67) was employed for the adsorption of Cr(VI) under a neutral solution. It was discovered that the ZIF-67 demonstrated a high adsorption of Cr(VI) for the first (43.1 mg·g –1 ) and second run (40.2 mg·g –1 ). However, a self-sacrifice process of ZIF-67 was evidenced, possibly due to the oxidability of Cr(VI) and pH change, which resulted in a dramatically decrease of adsorption ability in the third run (16.6 mg·g –1 ). The adsorption process and its kinetics fitted the Langmuir model and pseudo-second-order rate equation and a multiple adsorption process was suggested.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Cleaner Production
·
2022
·
IF 11.072
Sun Qian,Wang Changlong,Zhang Lixin,Yang Yanzhao
The high pathogenicity to organisms and high destructiveness in the natural environment determine the utmost importance of removing Cr(VI) from water. Herein, thiourea crosslinked-amino modified graphene nanoflakes (TAGN) was prepared by simple ring opening reaction and silanization reaction and the Cr(VI) adsorption performance was investigated. Results manifested that TAGN presented three-dimensional porous structure with abundant folds and avoided agglomeration. The adsorption experiments indicated that the optimal test pH value was 2 and the most suitable adsorbent dosage was 1 g/L. Under the optimum adsorption conditions, TAGN exhibited an outstanding adsorption capacity of 193.77 mg/g for Cr(VI) in water. Various characterizations and tests such as Zeta potential , FTIR, XPS as well as isotherms and kinetics revealed that the adsorption of TAGN for Cr(VI) was more consistent with Freundlich isotherm model and pseudo-second-order kinetic model , confirming a multilayer chemisorption process dominated by multiple combination mechanisms: electrostatic interaction, reduction reaction, complexation and hydrogen bonding interaction. Under the condition of coexistence of multiple metal ions , the TAGN could still maintain superb selectivity of 63.9% towards Cr(VI). After ten cycling test, 81.8% removal efficiency of Cr(VI) was guaranteed. Therefore, TAGN possessed high adsorption capacity , excellent selectivity and prominent cyclic regeneration ability. This work provided a promising nanosorbent for the field of water cleaning, especially for the elimination of heavy metal ions .
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2018
·
IF 0
Sefiu Abolaji Rasaki,Bingxue Zhang,Siqi Liu,Tiju Thomas,Minghui Yang
ZnO@TiCN nanourchin composites are synthesized via a solid–solid separation process followed by a wet deposition method. The composite contains TiCN nanourchins, metallurgically connected to ZnO ; the system adsorbs Cr(VI) following a pseudo-first order kinetics. This heterostructure has substantial ability to thermochemically convert the adsorbed Cr (VI) to Cr (III). Complete removal of Cr (VI) is achieved, even in the <10 ppm concentration regime. The effect of reaction time, temperature, pH value, adsorbent loading, initial concentration of Cr (VI), and thermodynamic parameters are systematically investigated. Van’t Hoff’s plot based analysis indicates that the entropy change associated with physisorption process involved is significantly positive (∼18 kJ/mol K). The process is also substantially endothermic (△H ∼ 5 kJ/mol). Kinetics improves with temperature up to 90 °C. The high entropy associated with the adsorption is attributed to a high heterogeneity factor of ∼3.9. Pseudo-second order is the best kinetic model to describe the adsorption of Cr(VI) onto the surface of ZnO@TiCN; both Freundlich and Langmuir isotherms describe the adsorption observed. Over 4 regeneration cycles, an adsorption capacity retention of >90% is observed. This novel adsorbent, with its hierarchical structure, and properties reported here, suggest that it could find applications in contemporary waste water treatment processes.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Qianwei Liang,Hanjin Luo,Junjie Geng,Jingda Chen
A novel nitrogen-doped ultra-light graphene oxide (GO) aerogel with three-dimensional (3D) network structure is used for removing of Cr(VI) from aqueous solution, which is fabricated by a facile one step hydrothermal self-assembly process and an environmentally friendly freeze-drying technique. GO and organic amine are used as the precursors to synthesize the aerogels, in which pyrrole and Tetraethylenetetramine (TEPA) are introduced as nitrogen sources to obtain the amino functional groups, meanwhile, they also play the roles as cross-linking agents to control the assembly of GO sheets in the 3D structure. The obtained TEPA/polypyrrole/GO aerogel (TPGA) has a high adsorption capacity for Cr(VI) anions (up to 408.48 mg/g) at an optimal pH of 2.0. The kinetics process of Cr(VI) adsorption on TPGA can be fitted well with the pseudo-second-order kinetic model. The mechanism of adsorption is analyzed by intraparticle diffusion and external film diffusion models, which indicates that the overall rate of Cr(VI) adsorption process is influenced by multi-steps. The isotherm and thermodynamic studies confirms that adsorption of Cr(VI) on TPGA is a spontaneous and endothermic process in the monolayer adsorption pattern. Furthermore, the prepared TPGA exhibits a good regeneration ability and satisfactory recovery for Cr(VI) anions in practical water samples. This work provides a simple and environmentally friendly method to synthesize the nitrogen-doped GO aerogel, which show a great potential and promise for practical application in the field of waste water treatment.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
·
2021
·Vol. 27
·期 3
·640-654
·
IF 1.993
Xiaoqi Liu,Yan Liu,Ting'an Zhang
This study aimed to prepare an efficient, cost-effective, and separable magnetic zeolite/chitosan composite (MZFA/CS) adsorbent from solid waste to deal with the water pollution of Cr(VI). The MZFA/CS was characterized by X-ray fluorescence (XRF), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM) techniques. Then, the effect of pH, temperature, initial concentration of Cr(VI) ions, and contact time was considered in the study. For a sorbent dose of 0.1 g in 50 mL of a Cr(VI) solution, at a contact time of 30 min, temperature of 30°C, and a pH of 3, an adsorption capacity ( q e ) of 16.96 mg g −1 was achieved. Adsorption kinetics and isotherm data obtained for all adsorption systems were well-fitted by pseudo-second-order and Langmuir models, respectively. The thermodynamic study suggested that the adsorption process is spontaneous and endothermic in nature. In summary, the adsorbent with better separability ( Ms = 16.83 emu g −1 ) and adsorbability was successfully fabricated.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 34
·e52799
·
IF 3.057
Wei Jia,Jiang Du,Ming Jiang,Mengying Zhang,Enlin Han,Hongqing Niu,Dezhen Wu
In order to overcome the shortcomings of nanofiber membranes such as low mechanical properties and poor acid resistance, amino-rich functionalized polyimide (PI)-polyethyleneimine (PEI) fibers were successfully prepared in the study. The structure and morphology in each functionalization step were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), static contact angle, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS) measurements. The adsorption kinetics analysis showed that the adsorption process followed a pseudo-second-order model, and the adsorption isotherm could be described better by the Langmuir model indicating the adsorption process was mainly chemical and homogeneous monolayer adsorption. Furthermore, the maximum adsorption capacity based on the Langmuir model was about 50 mg g −1 , and the calculated thermodynamic parameters demonstrated an endothermic process. Meantime, the PEI-grafted PI fibers also exhibited good regeneration performance and stable tensile strength during recycling tests process. In the first 3 adsorption–desorption cycles, the removal efficiency and tensile strength of PI-PEI fibers could be maintained up to 60.44% and 89.29% of the initial adsorption, respectively. This work achieved the function of removing Cr (VI) by combining the excellent high temperature resistance, acid resistance, and mechanical properties of PI fibers.
研究领域:
材料科学
·
环境工程
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）