The development of low-cost adsorbent with excellent adsorption property remains a big challenge. Herein, the functionalization of natural peach gum polysaccharide (PGP) with multiple amine groups for the removal of toxic Cr(VI) ions from water was studied. The obtained PGP-NH2 gel exhibited high-removal efficiency (>99.5%) toward Cr(VI) ions, especially with relatively low initial concentration of Cr(VI) ions (≤250 mg/L). The influences of pH, ionic strength, contact time, initial concentration, and temperature on the adsorption of Cr(VI) ions were systematically investigated. The PGP-NH2 gel showed rapid adsorption rate and could reach adsorption equilibrium within about 40 min. The Cr(VI) ion uptake process could be described by pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacity of PGP-NH2 gel could reach 188.32 mg/g. Thermodynamic investigation results indicated the spontaneous and exothermic characteristic of the uptake process. Moreover, the PGP-NH2 gel also exhibited favorable reusability, and 135.52 mg/g of adsorption capacity was retained even after being reused for five times. Considering its low cost and superior uptake property, the PGP-NH2 gel holds a great promise for employing as an adsorbent to treat Cr(VI) ion-containing wastewater.

中文翻译：

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天然桃胶多糖具有多个胺基的简便功能，可从水中高效去除有毒六价铬（Cr（VI））离子。

具有优异的吸附性能的低成本吸附剂的开发仍然是一个巨大的挑战。本文中，研究了具有多个胺基的天然桃胶多糖（PGP）的功能化，用于从水中去除有毒的Cr（VI）离子。所得的PGP-NH2凝胶对Cr（VI）离子具有较高的去除效率（> 99.5％），尤其是相对较低的Cr（VI）离子初始浓度（≤250mg / L）。系统地研究了pH，离子强度，接触时间，初始浓度和温度对Cr（VI）离子吸附的影响。PGP-NH2凝胶显示出快速的吸附速率，并且可以在约40分钟内达到吸附平衡。Cr（VI）离子的吸收过程可以用伪二级动力学模型和Langmuir等温模型描述。PGP-NH2凝胶的最大吸附量可达188.32 mg / g。热力学研究结果表明吸收过程的自发和放热特征。另外，PGP-NH 2凝胶也显示出良好的可重复使用性，甚至在重复使用五次后仍保留了135.52 mg / g的吸附容量。考虑到其低成本和优异的吸收性能，PGP-NH2凝胶作为吸附剂处理含Cr（VI）离子的废水具有广阔的前景。