Abstract：
Present study focuses on the use of a biodegradable and cost-effective cation exchanger for removal of Cr (VI) metal ions from water sources. Semi-IPN was prepared through grafting of acrylamide onto agar-polyvinyl alcohol backbone in presence of boric acid and ammonium per sulphate as crosslinker-initiator system. Graft copolymer was converted to cation exchanger through phosphorylation. Characterization was done using methods such as FTIR, SEM-EDX and XRD. Semi-IPN exhibited higher thermal resistance. The findings revealed that the optimum conditions for Cr (VI) removal are pH = 4.0; contact time (min) = 360; adsorbent dose (mg) = 125 and metal ion concentration(mg/L) =2. The adsorption kinetics of Cr (VI) ions are best fit by the pseudo second order kinetic with 0.99 R2 and Kf (rate constant) was found to be 0.97 thereby supporting the Freundlich isotherm. The adsorption isotherm models used in this study were consistent with the Freundlich model, but the pseudo second order model was the most accurate description of the adsorption kinetics. The present investigation showed an excellent potential with 85 % adsorption capacity for the removal of Cr (VI). Moreover, reusability studies showed that the cation exchanger can be used effectively up to four cycles.
摘要：
本研究的重点是使用可生物降解且具有成本效益的阳离子交换剂从水源中去除Cr（VI）金属离子。在硼酸和过硫酸铵作为交联剂-引发剂体系的存在下，通过将丙烯酰胺接枝到琼脂-聚乙烯醇主链上来制备半IPN。接枝共聚物通过磷酸化转化为阳离子交换剂。使用FTIR等方法进行表征，SEM-EDX和XRD。半IPN表现出更高的耐热性。结果表明，去除Cr（VI）的最佳条件为pH=4.0；接触时间（min）=360；吸附剂剂量（mg）=125，金属离子浓度（mg/L）=2。Cr（VI）离子的吸附动力学最好通过伪二级动力学拟合，其中0.99R2和Kf（速率常数）为0.97，从而支持Freundlich等温线。本研究中使用的吸附等温线模型与Freundlich模型一致，但伪二阶模型是对吸附动力学最准确的描述。本研究显示了去除Cr（VI）的优异潜力，具有85％的吸附能力。此外，可重用性研究表明，阳离子交换剂可以有效地使用四个周期。
