Institute of Ecological and Environmental Sciences, Sichuan Agricultural University, Chengdu, Sichuan 611130, China.
Department of Chemical Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030, China.
Sci Total Environ. 2020 Jan 20;701:134363. doi: 10.1016/j.scitotenv.2019.134363. Epub 2019 Sep 12.
Heavy metals (e.g., arsenic (As)) and tetracycline (TC) usually coexist in wastewater from livestock farm, whereas the co-adsorption behaviours and mechanisms of As(V) and TC were not well-known. This study investigated the adsorption and co-adsorption of As(V) and TC by a novel yttrium-immobilized-graphene oxide-alginate hydrogel (Y-GO-SA) to explore the adsorption behaviours and mechanisms. The adsorption of As(V) and TC was pH-dependent. The maximum adsorption capacities under the studied concentrations were 273.39 mg/g for As(V), and 477.9 mg/g for TC, respectively, which are much higher than many other reported adsorbents. Furthermore, As(V) adsorption was due to ion exchange between hydroxyl groups and HAsO groups and H-bonds formed with O-containing groups on Y-GO-SA, and the adsorption of TC by Y-GO-SA was mainly ascribed to electrostatic interaction, H-bonds, π - π EDA interaction, n-π EDA interaction, and cation-bonding bridge effects. The co-adsorption of As(V) and TC in binary system indicated that the presence of TC obviously suppressed the adsorption of As(V) due to the competition for active sites, whereas the effect of presence of As(V) on adsorption of TC can be negligible due to the balance contributions from its contrary effects, i.e. enhancement (anion-π interaction) and reduction (competition for Y ions) in TC adsorption. Finally, the hydrogels performed well in the treatment of livestock farm waste water. It can be anticipated that the prepared 3D hydrogel can be used as a powerful adsorbent in the practical application of waste water treatment, owing to its easy separation, high adsorption and good reusability.
重金属（如砷（As））和四环素（TC）通常共存于来自养殖场的废水中，而 As(V)和 TC 的共吸附行为和机制尚未得到很好的了解。本研究通过一种新型的钇固定化氧化石墨烯-海藻酸钠水凝胶（Y-GO-SA）来研究 As(V)和 TC 的吸附和共吸附，以探索吸附行为和机制。As(V)和 TC 的吸附受 pH 值影响。在研究浓度下，As(V)和 TC 的最大吸附容量分别为 273.39 mg/g 和 477.9 mg/g，均远高于许多其他报道的吸附剂。此外，As(V)的吸附是由于羟基和 HAsO 基团之间的离子交换以及 Y-GO-SA 上含氧基团形成的氢键，而 Y-GO-SA 对 TC 的吸附主要归因于静电相互作用、氢键、π-π EDA 相互作用、n-π EDA 相互作用和阳离子键桥效应。二元体系中 As(V)和 TC 的共吸附表明，TC 的存在由于竞争活性位点，明显抑制了 As(V)的吸附，而 As(V)的存在对 TC 的吸附影响可以忽略不计，因为其相反的影响（阴离子-π 相互作用）和减少（对 Y 离子的竞争）在 TC 吸附中达到平衡。最后，水凝胶在处理养殖场废水方面表现良好。可以预期，由于易于分离、高吸附和良好的可重复使用性，制备的 3D 水凝胶可以用作废水处理的有效吸附剂。
