Zirconia modified chitosan beads (Zr-CTS) have been synthesized as adsorbent for fluoride ions from water bodies. The beads have been characterized using FTIR, SEM, EDX, TG-DTA and BET surface area analysis. Batch adsorption parameters are performed for defluoridation of water using the prepared composite. The pH point of zero charge was found to be 5.7. Maximum efficiency of the adsorbent is observed at pH 4.0, with adsorbent dose of 40 mg per 25 mL of 25 ppm fluoride solution and adsorption period of 45 min. Under these conditions, Zr-CTS is found to have an adsorption capacity of 52.63 mg g^-1 in accordance with Freundlich adsorption isotherm. Thermodynamics parameters reveal that the process of adsorption was spontaneous, exothermic and leading to increase in entropy. The process follows pseudo-second-order kinetics model. The used material is regenerated using 5% NaCl solution and could be reused in multiple cycles adding greener dimension.

中文翻译：

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氧化锆-壳聚糖珠粒是用于水脱氟的高效吸附剂

已经合成了氧化锆改性的壳聚糖珠子（Zr-CTS）作为水体中氟离子的吸附剂。珠子已经使用FTIR，SEM，EDX，TG-DTA和BET表面积分析进行了表征。使用制备的复合材料进行批吸附参数以对水进行脱氟。发现零电荷的pH值为5.7。在pH 4.0时观察到吸附剂的最大效率，吸附剂剂量为每25 mL 25 ppm氟化物溶液40 mg，吸附时间为45分钟。在这些条件下，发现Zr-CTS的吸附容量为52.63 mg g ^-1按照Freundlich的吸附等温线。热力学参数表明吸附过程是自发的，放热的，并导致熵增加。该过程遵循伪二级动力学模型。用过的材料使用5％NaCl溶液再生，可以多次循环使用，从而增加了绿色尺寸。