Excessive fluoride in groundwater is becoming a worldwide environmental problem increasing the risk of fluorosis. In this study, an eco-friendly new defluorination resin (Al-CPCM) was synthesized by a modified emulsion method. The skeleton of the resin is cross-linked N-methylene phosphonic chitosan and the incorporated Al(III) is the binding site of fluoride. The batch experiments conducted using pure synthetic sodium fluoride solutions showed that Al-CPCM exhibited a fast fluoride removal within 30 min, maintained stability from pH 3–10. Effect of presence of other anions was studied by adding one extra anion at a time and it was observed that presence of phosphate and carbonate ions significantly degraded the adsorption capacity of the resin. The maximum adsorption capacity was 15.067 mg/g at 30 °C and the adsorption behavior was well-fitted with the pseudo-second-order kinetic model and Hill isotherm model. The results of in-situ flow ATR-FTIR and thermodynamics studies show that the fluoride adsorption dominantly implemented by ion exchange with surface hydroxyl of chelated Al³⁺ in the resin. In addition, the adsorption capacity only decreased by 5.5% after six successive sorption/desorption cycles, indicating a better regeneration efficiency among other defluorinated resins. Finally, a column experiment was performed using ground water and, in this case, it is observed that the adsorption capacity of the resin was much lower and the decrease in adsorption capacity after elution/regeneration is was larger (both mainly due to the presence of alternate anions/cations in the feed solution). More elaborate column experiments with real-life groundwater samples are required to assess the suitability of the proposed resin for use as a commercial adsorbent.

地下水中过量的氟化物正在成为一个世界性的环境问题，增加了氟中毒的风险。本研究采用改性乳液法合成了一种环保型新型脱氟树脂（Al-CPCM）。树脂的骨架是交联的N-亚甲基膦酸壳聚糖，掺入的Al(III)是氟化物的结合位点。使用纯合成氟化钠溶液进行的批量实验表明，Al-CPCM 在 30 分钟内表现出快速的氟化物去除，在 pH 3-10 范围内保持稳定。通过一次添加一个额外的阴离子来研究其他阴离子存在的影响，并观察到磷酸根和碳酸根离子的存在显着降低了树脂的吸附能力。最大吸附量为15。067 mg/g 在 30 °C 吸附行为与准二级动力学模型和 Hill 等温线模型非常吻合。结果原位流动 ATR-FTIR 和热力学研究表明，氟化物吸附主要通过与螯合 Al ³⁺表面羟基的离子交换来实现在树脂中。此外，在连续六次吸附/解吸循环后，吸附容量仅下降了 5.5%，表明在其他脱氟树脂中具有更好的再生效率。最后，使用地下水进行了柱实验，在这种情况下，观察到树脂的吸附能力要低得多，而洗脱/再生后吸附能力的下降幅度更大（两者主要是由于存在进料溶液中的交替阴离子/阳离子）。需要对真实地下水样品进行更精细的柱实验，以评估所提出的树脂用作商业吸附剂的适用性。