纳米氧化铁/蔗渣活性炭对水中As(Ⅴ)的动态吸附研究

Dynamic Adsorption Characteristics of As(Ⅴ) to Nanometer Iron Oxide/Bagasse Activated Carbon Composite Adsorbent

研究了纳米氧化铁/蔗渣活性炭复合吸附剂(NAC)对As(Ⅴ)的动态吸附,探讨了As(Ⅴ)初始浓度、溶液p H、床层高度、进水流量对穿用透曲线的影响,研究了NAC的再生和循环使用效果。结果表明,随着初始As(Ⅴ)浓度和进水流量的增加,穿透时间缩短;随着床层高度的增加,穿透时间延长;穿透时间随p H值的变化顺序为:t_(b(pH=3.3))<t_(b(p H=9.8))<t_(b(p H=6.8))。Thomas模型常数(K_(TH))和Adams-Bohart模型常数(K_(AB))均随着初始As(Ⅴ)浓度、床层高度的增大而减小,随着进水流量的增加而增大。K_(TH)随pH的升高而减少,K_(AB)随pH的变化规律是:K_(AB(pH=6.8))<K_(AB(pH=3.3))<K_(AB(p H=9.8))。NAC经1 mo L/L盐酸洗脱450 min后,再生液中As(Ⅴ)浓度<10μg/L,As(Ⅴ)的解吸率为33.56%。

Fixed-bed experiments were carried out by using a nanometer iron oxide/bagasse activated carbon composite adsorbent （NAC） as adsorbent for the dynamic adsorption of As （ V ） from aqueous solution. The effect of As （ V ） feed concentration, pH value, bed height and inlet flow rate on the breakthrough curves were investigated and the regeneration and recycle using of NAC were investigated as well. The results showed that the breakthrough time decreases with the increase of inlet As （V） concentration and inlet flow rate of arsenic solution while increasing with the increase of bed height. The rule of change of breakthrough time with pH value is tb（pH=3.3））〈tb（pH=9.8）〈tb（pH=6.8）. Kinetic constants of Thomas model（KTH） and AdamsBohart model （KAB） decreases with the increase of inlet As（V） concentration and bed height while increasing with the increase of inlet flow rate of arsenic solution. KTH decreases with the increase of pH value.The change rule of KAB with pH value is KAB（pH=6.8）〈KAB（pH=3.3）〈KAB（pH=9.8）.The As（V） concentration of regeneration solution was lower than 10 μg/L after NAC was chemically regenerated by 1 mol/L of HCl solution and a regeneration efficiency of 33.56% was observed.