载铁(β-FeOOH)球形棉纤维素吸附剂去除地下水砷(Ⅲ)的研究

Elimination of As(Ⅲ) from Groundwater by Bead Cellulose Adsorbent Loaded with Fe(β-FeOOH)

制备了一种载铁(β-FeOOH)球形棉纤维素吸附剂, 并用于地下水中As(Ⅲ)的去除. 吸附剂对As(Ⅴ)和As(Ⅲ)在吸附容量、选择性和速率等方面都具有良好的性能, 无需预氧化As(Ⅲ), 其适用pH范围宽, 不必调节原水的pH. 吸附剂孔隙度大, 机械强度好, 活性成分铁的载入量高, 吸附As(Ⅲ)的活性好. Langmuir和Freundlich方程能较好地描述吸附平衡方程, 其吸附动力学符合Lagergren准二级方程. 吸附 As(Ⅲ) 的最佳pH范围为6～9. SO2-4和Cl-等干扰离子均不影响As(Ⅲ)的去除. 柱吸附实验表明, 即使在较高流速和As(Ⅲ)进水浓度下, 吸附剂对As(Ⅲ)的去除依然具有很高的穿透容量和饱和容量. 吸附剂可以用NaOH溶液再生, 洗脱和再生效率较高. 活性成分β-FeOOH形态稳定, 柱实验和再生时铁均无泄漏.

A new adsorbent, bead cellulose loaded with Fe hydroxide(β-FeOOH) was prepared and applied to the removal of arsenite from groundwater. The adsorbent has perfect properties in -{As(Ⅴ)-} and As(Ⅲ) adsorption capacity, selectivity and kinetics. There is no need of pH adjusting and preoxidation during the arsenite removal. The adsorbent is porous and has excellent mechanical properties. The adsorbent has a high content of Fe, which is the reactive center with a high reactivity for sorption of arsenite. The sorption kinetic data can be described by the Lagergren pseudo-second order rate equation. Arsenate elimination was favored at pH=6-_9. The addition of chloride, sulfate did not affected the arsenite removal efficiency. The column experiment indicated that the breakthrough and saturation capacity were large with high velocity flow and influent arsenite concentration. The adsorbent can be generated with NaOH solutions, and the desorption and regeneration process were effective. The β-FeOOH loaded in the bead cellulose was chemically stable during the column experiment and regeneration.