Effect of pre-treatment of bentonite with sodium and calcium ions on phosphate adsorption onto zirconium-modified bentonite

Lin, Jianwei; Bo, Jiang; Zhan, Yanhui

doi:10.1016/j.jenvman.2018.03.079

Cited by 101 publications

(36 citation statements)

References 60 publications

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“…Due to providing worthy information on the reaction pathways and adsorption mechanisms, adsorption kinetics analysis plays a vital role in the adsorption system [ 57 ]. The mass transfer and chemical reaction mechanisms of the adsorptive removal of phosphate onto VPum and VSco can be examined by various kinetic models, namely Lagergren pseudo-first-order, pseudo-second-order, and Weber and Morris intra-particle diffusion kinetic models [ 58 , 59 ]. Therefore, their validity for use with the experimental adsorption data for phosphate onto VPum and VSco was investigated.…”

Section: Resultsmentioning

confidence: 99%

“…This is because the resistance to the up-taking of the adsorbate onto the adsorbents’ surfaces is higher, and the active site for adsorption gets saturated at higher concentrations [ 10 ]. In contrast, phosphate removal capacity, q t , increased with increasing the initial phosphate concentration due to the higher driving forces provided by the higher initial concentrations, which were able to resist the mass transfer between the solid surface and aqueous solution [ 59 ], which enables the adsorbate to remain on the surface of the adsorbents. Furthermore, for the initial phosphate concentration in the range of 5 to 25 mg·L −1 , the amount of phosphate adsorbed decreased in the order of VPum > VSco.…”

Section: Resultsmentioning

confidence: 99%

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Adsorptive Removal of Phosphate from Aqueous Solutions Using Low-Cost Volcanic Rocks: Kinetics and Equilibrium Approaches

2021

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The contamination of surface and groundwater with phosphate originating from industrial and household wastewater remains a serious environmental issue in low-income countries. Herein, phosphate removal from aqueous solutions was studied using low-cost volcanic rocks such as pumice (VPum) and scoria (VSco), obtained from the Ethiopian Great Rift Valley. Batch adsorption experiments were conducted using phosphate solutions with concentrations of 0.5 to 25 mg·L−1 to examine the adsorption kinetic as well as equilibrium conditions. The experimental adsorption data were tested by employing various equilibrium adsorption models, and the Freundlich and Dubinin-Radushkevich (D-R) isotherms best depicted the observations. The maximum phosphate adsorption capacities of VPum and VSco were calculated and found to be 294 mg·kg−1 and 169 mg·kg−1, respectively. A pseudo-second-order kinetic model best described the experimental data with a coefficient of correlation of R2 > 0.99 for both VPum and VSco; however, VPum showed a slightly better selectivity for phosphate removal than VSco. The presence of competitive anions markedly reduced the removal efficiency of phosphate from the aqueous solution. The adsorptive removal of phosphate was affected by competitive anions in the order: HCO3− >F− > SO4−2 > NO3− > Cl− for VPum and HCO3− > F− > Cl− > SO4−2 > NO3− for VSco. The results indicate that the readily available volcanic rocks have a good adsorptive capacity for phosphate and shall be considered in future studies as test materials for phosphate removal from water in technical-scale experiments.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Adsorptive Removal of Phosphate from Aqueous Solutions Using Low-Cost Volcanic Rocks: Kinetics and Equilibrium Approaches

2021

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“…The acid-activated process is the most widely-used technique for bentonite treatment before its further usage. After the acid-activation, the bentonite can be modified easily, and its adsorption ability can be improved significantly [ 41 ]. Orange 1, with a purity of 99%, was obtained from Shanghai Aladdin Bio-Chem Technology Co. Ltd., Shanghai China.…”

Section: Methodsmentioning

confidence: 99%

Surface Modification of Bentonite with Polymer Brushes and Its Application as an Efficient Adsorbent for the Removal of Hazardous Dye Orange I

Guo

Umar

et al. 2020

Nanomaterials

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Poly(2-(dimethylamino)ethyl methacrylate)-grafted bentonite, marked as Bent-PDMAEMA, was designed and prepared by a surface-initiated atom transfer radical polymerization method for the first time in this study. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA) were applied to characterize the structure of Bent-PDMAEMA, which resulted in the successful synthesis of Bent-PDMAEMA. As a cationic adsorbent, the designed Bent-PDMAEMA was used to remove dye Orange I from wastewater. The adsorption property of Bent-PDMAEMA for Orange I dye was investigated under different experimental conditions, such as solution pH, initial dye concentration, contact time and temperature. Under the optimum conditions, the adsorption amount of Bent-PDMAEMA for Orange I dye could reach 700 mg·g−1, indicating the potential application of Bent-PDMAEMA for anionic dyes in the treatment of wastewater. Moreover, the experimental data fitted well with the Langmuir model. The adsorption process obeyed pseudo-second-order kinetic process mechanism.

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“…An increase in CR removal was observed by increasing slat concentration of NaCl and CaCl 2 from 0 to 0.05 M and became constant onward. The increase in CR removal with increasing salts' concentration could be credited to decrease in the electrostatic repulsion between CR anions, thus accelerating CR aggregation (Lin et al, 2018). In addition, compared with NaCl, higher enhancement in CR removal was observed by the presence of CaCl 2 , which could be due to the presence of more positive charge on Ca 2+ than Na + , hence bitterly neutralizing negative charges in aqueous solution.…”

Section: Effect Of Ionic Strength and Surfactant On Cr Adsorptionmentioning

confidence: 98%

Citric Acid Modified Bentonite for Congo Red Adsorption

et al. 2019

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Raw bentonite (RB) was chemically modified by citric acid (CA) to obtain a low-cost and environment-friendly citric acid incorporated bentonite (CAB) adsorbent, which was applied for the adsorptive removal of Congo Red (CR). The effect of adsorbent dosage, contact time, ionic strength, surfactant, and pH on adsorption was investigated. Adsorption equilibrium data fitted well with Langmuir model while the Langmuir adsorption capacity of CR on CAB reached up to 384 mg•g −1. Furthermore, CR adsorption on CAB followed pseudo-second kinetic model while intra-particle diffusion was not the only rate-limiting step as determined from intra-particle diffusion model investigation. RB and CAB were characterized by XRD, FT-IR, and BET techniques. A proposed mechanism for the adsorption of CR over CAB suggested the chemical adsorption phenomenon is mainly controlled by chelation, hydrogen bonding, and fixing.

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Effect of pre-treatment of bentonite with sodium and calcium ions on phosphate adsorption onto zirconium-modified bentonite

Cited by 101 publications

References 60 publications

Adsorptive Removal of Phosphate from Aqueous Solutions Using Low-Cost Volcanic Rocks: Kinetics and Equilibrium Approaches

Adsorptive Removal of Phosphate from Aqueous Solutions Using Low-Cost Volcanic Rocks: Kinetics and Equilibrium Approaches

Surface Modification of Bentonite with Polymer Brushes and Its Application as an Efficient Adsorbent for the Removal of Hazardous Dye Orange I

Citric Acid Modified Bentonite for Congo Red Adsorption

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