Adsorption is one of the most promising techniques for large-scale application in phosphate-containing wastewater treatment and the synthesis of efficient adsorbents is the core of the process. High efficiency adsorbent include inorganic adsorbents and organic adsorbents, and the chitosan performs better adsorption capacity because of readily biodegradable and abundant amino functional groups. In this work, a kind of calcium-modified chitosan microspheres (Ca-CTS gel) has been gained through in-situ precipitation for absorbing phosphate from simulation wastewater. The influence factors of the synthesis conditions including crosslinking agent addition, mental ions types, and Ca²⁺ loading amount, etc., on the adsorption efficiency have been researched. The results showed that the metal ions modified chitosan represented by La³⁺ modified chitosan was significantly different from Ca²⁺ modified chitosan in loading principle. The characterization results indicated that the adsorption mechanism belonged to the precipitation conversion between Ca(OH)₂ and CaHPO₄·2H₂O. The adsorption kinetics and thermodynamics results showed that the adsorption reaction was endothermic and spontaneous, and the Langmuir-fitted maximum adsorption capacity was 23.7 mg/g at 25 °C. The adsorption experiment results also showed that the other anions, i.e., SO₄²⁻ and CO₃²⁻ have a negative influence on phosphate removal, attributing to the smaller Ksp values of their calcium salts. In addition, the dynamic phosphate-adsorption curves have been obtained under different operating conditions for evaluating the industrial application prospect of the as-prepared Ca-CTS gel.

吸附是大规模应用于含磷废水处理的最有前途的技术之一，高效吸附剂的合成是该过程的核心。高效吸附剂包括无机吸附剂和有机吸附剂，壳聚糖由于易于生物降解和丰富的氨基官能团，具有更好的吸附能力。在这项工作中，通过原位沉淀吸收模拟废水中的磷酸盐，获得了一种钙修饰的壳聚糖微球（Ca-CTS凝胶）。交联剂添加量、金属离子种类、Ca ^{2+ 等}合成条件的影响因素载量等对吸附效率的影响进行了研究。结果表明，以La ³⁺改性壳聚糖为代表的金属离子改性壳聚糖在负载原理上与Ca ²⁺改性壳聚糖存在显着差异。表征结果表明吸附机理属于Ca(OH) ₂和CaHPO ₄ ·2H ₂ O之间的沉淀转化。吸附动力学和热力学结果表明吸附反应是吸热自发的，Langmuir拟合最大吸附25 °C 时的容量为 23.7 mg/g。吸附实验结果还表明，其他阴离子，即 SO ₄ ^2-和 CO₃ ²⁻对磷酸盐去除有负面影响，归因于其钙盐的较小Ksp值。此外，还获得了不同操作条件下的动态磷酸盐吸附曲线，以评估所制备的 Ca-CTS 凝胶的工业应用前景。