TecNM/Instituto Tecnológico de Aguascalientes, Av. Adolfo López Mateos No. 1801 Ote, C.P. 20256, Aguascalientes, Ags., Mexico.
TecNM/Instituto Tecnológico de Aguascalientes, Av. Adolfo López Mateos No. 1801 Ote, C.P. 20256, Aguascalientes, Ags., Mexico.
J Environ Manage. 2021 Sep 1;293:112877. doi: 10.1016/j.jenvman.2021.112877. Epub 2021 Jun 4.
Anodizing wastewater contains principally phosphate (PO) anions according to previous studies, but with the purpose to promote water reuse in this type of industry, a complete characterization of wastewater was made to remove other anions and cations also present in significant concentration. Particularly, the adsorption of sodium (Na), potassium (K), fluoride (F), sulfate (SO) and phosphate (PO) was studied using different sorbents such as: coconut shell activated carbon, bone char, bituminous coal activated carbon, natural zeolite, silica, anionic and cationic exchange resins, a coated manganese-calcium zeolite, coconut shell activated carbon containing iron and iron hydroxide. All sorbents were characterized using FT-IR spectroscopy, potentiometric titration, nitrogen adsorption isotherms at 77 K, X-ray diffraction and SEM/EDX analysis to study the adsorption mechanism. The adsorption studies were performed in batch systems under constant agitation using both standard solutions of each ion and real anodizing wastewater. Results showed that, in general, the adsorption of all anions and cations is higher when mono-component standard solutions were used, since in the anodizing wastewater all species are competing for the active sites of the adsorbent. Na present in anodizing wastewater was efficiently adsorbed on coated manganese-calcium zeolite (20.55 mg/g) and natural zeolite (18.55 mg/g); while K was poorly adsorbed on all sorbents (less than 0.20 mg/g). Anions such as F, SO and PO, were better adsorbed on the anionic resin (0.17, 45.38 and 2.92 mg/g, respectively), the iron hydroxide (0.14, 7.96 and 2.87 mg/g, respectively) and the bone char (0.34, 8.71 and 0.27 mg/g, respectively). All these results suggest that adsorption is a promising tertiary treatment method to achieve water reuse in the anodizing industry.
根据之前的研究，阳极氧化废水主要含有磷酸盐（PO）阴离子，但为了促进该类型工业的水再利用，对废水进行了全面的特性分析，以去除其他同样存在于显著浓度下的阴离子和阳离子。特别是，使用不同的吸附剂如椰子壳活性炭、骨炭、烟煤活性炭、天然沸石、硅、阴离子和阳离子交换树脂、涂覆的锰钙沸石、含铁和氢氧化铁的椰子壳活性炭，研究了对钠离子（Na）、钾离子（K）、氟离子（F）、硫酸根（SO）和磷酸根（PO）的吸附。所有吸附剂均使用傅里叶变换红外光谱法（FT-IR 光谱法）、电位滴定法、77 K 下的氮气吸附等温线、X 射线衍射和 SEM/EDX 分析进行了表征，以研究吸附机理。在恒搅拌条件下，使用各离子的标准溶液和实际的阳极氧化废水，在批量系统中进行了吸附研究。结果表明，一般来说，当使用单一成分标准溶液时，所有阴离子和阳离子的吸附效果都更高，因为在阳极氧化废水中，所有物质都在竞争吸附剂的活性位点。阳极氧化废水中的 Na 高效地被涂覆的锰钙沸石（20.55 mg/g）和天然沸石（18.55 mg/g）吸附；而 K 则被所有吸附剂吸附的效果较差（低于 0.20 mg/g）。阴离子如 F、SO 和 PO ，在阴离子树脂（分别为 0.17、45.38 和 2.92 mg/g）、氢氧化铁（分别为 0.14、7.96 和 2.87 mg/g）和骨炭（分别为 0.34、8.71 和 0.27 mg/g）上的吸附效果更好。所有这些结果表明，吸附是一种很有前途的三级处理方法，可以实现阳极氧化工业的水再利用。
