| Abstrakt: |
A cost-effective adsorbent (AWS@Zr) was synthesized from walnut shell using Zirconium and amino group modification for the uptake of 2,4-dichlorophenoxyacetic acid (2,4-D) and phosphate (PO43−). Characterization of the adsorbents revealed a significant difference in the physicochemical parameters of pristine and functionalized walnut shell. Langmuir model was observed to predict adsorption of 2,4-D, while Freundlich model best-fitted PO43− adsorption with chemisorption being the principal underlying mechanism. The adsorption phenomena were pH dependent with Langmuir maximum capacity of 227.4 ± 5.4 mg g−1 and 73.9 ± 3.2 mg g−1 for 2,4-D and PO43−, respectively. Kinetic models were also used to analyze the experimental data, and remarkable determined coefficients favor the pseudo-second-order kinetic model for the batch systems. The column experiments were carried out as a function of adsorbates flow rate, initial feed of 2,4-D and PO43− concentration, bed depth. The results indicated both Thomas and Clark models could predict uptake of 2,4-D and phosphate with Thomas maximum capacity as 195.5 ± 1.0 for 2,4-D and 87.4 ± 0.7 mg g−1 for PO43− at optimum flow rate of 10 mL min−1 and bed depth of 6 cm. Moreover, the column isotherm studies revealed that the Langmuir model predicted the adsorption data of PO43−, and 2,4-D, which was consistent with batch adsorption of 2,4-D. The studied pollutants onto AWS@Zr are PO43− > 2,4-D based on the β−1 obtained from the column's mass transfer analysis. Adsorption–desorption studies revealed the reusability potentials of AWS@Zr. Zr and amino in surface of AWS@Zr play major role during removal of 2,4-D and PO43−. There is potential for AWS@Zr to remove some anionic pollutants from solution. [ABSTRACT FROM AUTHOR] |
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