An Efficient and Regenerable Quaternary Starch for Removal of Nitrate from Aqueous Solutions

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• 作者：Kalpana Chauhan ; Jasvinder Kaur ; Prem Singh ; Poonam Sharma ; Praveen Sharma ; Ghanshyam S. Chauhan
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2016
• 出版时间：March 9, 2016
• 年：2016
• 卷：55
• 期：9
• 页码：2507-2519
• 全文大小：842K
• ISSN：1520-5045

文摘

This paper presents a study of NO₃^– ions sorption from an aqueous solution using quaternary starch derivatives. For this, the derivatization was carried out by an improvised method for the synthesis of a gemini-like structure, which is unique and has two quaternary ammonium functionality per anhydroglucose units of starch. Mohr’s method was used to characterize the synthesized bis-quaternary starch as chloride ion content, and the results supported a chloride content of 13.5–14.4% with the total ion exchange capacity of 3.8–4.2 mequiv/g. A series of batch experiments were conducted to examine the effects of structure, contact time, concentration, pH, and effect of co-ions on the sorption of NO₃^–. The results showed an increase in sorption capacity with an increase in the concentration of NO₃^–, while the presence of competing anions such as PO₄^3–, HCO₃^–, and SO₄^2– showed marginal effect on the NO₃^– sorption capacity. The increase in pH from 4.0 to 6.5 also effected the NO₃^– sorption process marginally. Moreover, the quaternary starch exhibited 78.5% efficiency even after the eighth sorption–desorption cycle. The kinetic and thermodynamic adsorptions of NO₃^– ions from the aqueous solutions were also investigated for the synthesized quaternary starch derivative. The adsorption kinetics data were best described by the pseudo-second-order rate equation. The equilibrium data agreed well with the Langmuir model. The maximum capacity for quaternary starch can be deduced from the obtained correlation coefficients and was calculated at ≈205 mg/g in the isotherm model, which is preferential to the earlier reported commercialized Purolite technology. In conclusion, the bis-quaternary starch structure is successfully synthesized in uniform and high modification and shows significant potential for removal of NO₃^– ions from aqueous solution.