In this work, we discuss the ammonium nitrogen adsorption and reusability from aqueous solution by using poly(sodium acrylate) (PANa) hydrogels (Polymers 1–6) under different amount of crosslinker and initiator. The PANa hydrogels were synthesized from the neutralized acrylic acid (AA) monomer via free radical thermal polymerization by using ammonium persulfate (APS) as an initiator and N,N′‐methylene‐bisacrylamide (MBA) as a crosslinker. These polymers exhibited glass transition temperatures (T_g) of 68–88°C and T_d values (5% weight loss temperature) in the range of 190–221°C under nitrogen atmosphere. The PANa hydrogels had swollen ratios ranging from 387 to 4,063%, related to the crosslinking density. The final equilibrium adsorption capacity of the polymers was in the range of 20–39 ppm with an initial ammonium nitrogen concentration of 100 ppm. Among them, Polymer 3 without MBA crosslinker displayed the highest swollen characteristic along with the most efficient adsorption capacity. In comparison, the as‐prepared high crosslinking density hydrogels showed relative lower adsorption capability but higher reusability. The polymer composition in this work determines the ability to absorb and desorb ammonium nitrogen compound.

中文翻译：

---

聚丙烯酸钠从水溶液中吸附铵态氮：对交联剂和引发剂用量的影响

在这项工作中，我们讨论了在不同交联剂和引发剂条件下使用聚丙烯酸钠（PANa）水凝胶（聚合物1-6）在水溶液中对铵态氮的吸附和可重复利用性。PANa水凝胶是由中和的丙烯酸（AA）单体通过过硫酸铵（APS）作为引发剂和N，N'-亚甲基双丙烯酰胺（MBA）作为交联剂通过自由基热聚合反应合成的。这些聚合物的玻璃化转变温度（T _g）为68-88°C，T _d在氮气气氛下，温度值（失重温度的5％）在190–221°C范围内。PANa水凝胶的溶胀率为387至4063％，与交联密度有关。聚合物的最终平衡吸附容量在20-39 ppm范围内，氨氮的初始浓度为100 ppm。其中，没有MBA交联剂的聚合物3表现出最高的溶胀特性以及最有效的吸附能力。相比之下，所制备的高交联密度水凝胶显示出相对较低的吸附能力，但具有较高的可重复使用性。这项工作中的聚合物成分决定了吸收和解吸铵态氮化合物的能力。