Zhang Yu, Yang Min, Huang Xia
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
Chemosphere. 2003 Jun;51(9):945-52. doi: 10.1016/S0045-6535(02)00850-0.
The removal of arsenic(V) by a new Ce-Fe adsorbent was evaluated under various conditions. Under an initial As(V) of 1.0 mg l(-1), the adsorption capacity of the Ce-Fe absorbent was constant around a value of 16 mgg(-1) over a wide pH range (3-7), while a maximum adsorption capacity of 8.3 mgg(-1) was obtained over a narrow pH range around 5.5 for activated alumina, a conventional adsorbent. Kinetics of adsorption obeys a pseudo-first-order rate equation with the rate constant K(ad) as 1.84 x 10(-3) min(-1). The pattern of adsorption of As(V) by the adsorbent fitted well both the Langmuir and Freundlich models. A Langmuir Q(0) of 70.4 mgg(-1) was obtained at an initial pH of 5.0 and temperature of 20 degrees C, significantly higher than those of other adsorbents reported. Phosphate seriously inhibited the removal of As(V) while fluoride did not compete with As(V) even at an F/As molar ratio as high as 30, suggesting that the adsorption sites for As(V) and fluoride were different. Salinity, hardness, and other inorganic anions such as Cl(-), NO(3)(-), and SO(4)(2-) had no apparent effect on As(V) adsorption. Fourier transform infrared spectra of Ce-Fe adsorbent before and after As(V) adsorption demonstrated that M-OH groups plays an important role for As(V) ions removal in the adsorption mechanisms of Ce-Fe adsorbent.
在不同条件下评估了一种新型铈铁吸附剂对砷（V）的去除效果。在初始砷（V）浓度为1.0 mg l⁻¹时，铈铁吸附剂在较宽的pH范围（3 - 7）内吸附容量恒定在16 mgg⁻¹左右，而传统吸附剂活性氧化铝在pH约5.5的较窄范围内获得的最大吸附容量为8.3 mgg⁻¹。吸附动力学符合准一级速率方程，速率常数K(ad)为1.84×10⁻³ min⁻¹。吸附剂对砷（V）的吸附模式很好地拟合了朗缪尔和弗伦德利希模型。在初始pH为5.0、温度为20℃时获得的朗缪尔Q(0)为70.4 mgg⁻¹，显著高于报道的其他吸附剂。磷酸盐严重抑制砷（V）的去除，而氟化物即使在F/As摩尔比高达30时也不与砷（V）竞争，这表明砷（V）和氟化物的吸附位点不同。盐度、硬度以及其他无机阴离子如Cl⁻、NO₃⁻和SO₄²⁻对砷（V）的吸附没有明显影响。砷（V）吸附前后铈铁吸附剂的傅里叶变换红外光谱表明，M - OH基团在铈铁吸附剂的吸附机制中对砷（V）离子的去除起着重要作用。
