Removal of Cu(II) from CuSO4 Aqueous Solution by Mg-Al Hydrotalcite-like Compounds

Abstract

Hydrotalcite-like compound (HTlc) with a Mg/Al molar ratio of 2∶1 was synthesized by using a coprecipitation method and the sorption removal of Cu(II) by the Mg-Al HTlc sample from CuSO 4 solution was investigated. It was found that the Mg-Al HTlc showed a good sorption ability for Cu(II) from CuSO 4 solution, indicating that the use of hydrotalcite-like compounds as promising inorganic sorbents for the removal of heavy metal ions from water is possible. The sorption kinetics and the sorption isotherm of Cu(II) on the HTlc obeyed the pseudo-second order kinetic model and Langmuir equation, respectively. The percent removal of Cu(II) by the HTlc was strongly dependent on the initial pH of bulk solution. It increased sharply with the increase of initial pH value in the range of 5-7, and was relatively small in the initial pH range of 4-5, while it reached about 100% after initial pH was higher than 7. The presence of AlCl 3 might obviously lower the equilibrium sorption amount (q e ) of Cu(II) on the HTlc. However, the presences of NaCl and MgCl 2 might increase the q e . The presences of ligands (citric acid and EDTA) in the studied concentration range might obviously decrease the q e of Cu(II) on the HTlc. The removal mechanism of Cu(II) cations by HTlc in the presence of 2 4 SO anions may be attributed to the surface-induced precipitation of Cu(II) hydroxides and the surface complex adsorption by the linking effect of 2 4SO between the HTlc and Cu(II) cations, and the removal ability arising from the surface-induced precipitation is much higher than that from the linking effect of 2 4 SO -.

Removal of Cu2+, Pb2+ and Cd2+ by layered double hydroxide–humate hybrid. Sorbate and sorbent comparative studies

“…As determined by the Langmuir model fitting (Table 4), the maximum sorption increased in the sequence Cd (C m = 0.35 mmol g À1 ) Pb (C m = 0.48 mmol g À1 ) and Cu (C m = 0.75 mmol g À1 ). These values were comparable to those obtained for similar Mg-Al-LDHs: between 0.01 and 0.15 mmol g À1 for Cd 2+ sorption by Mg-Al-LDHs containing carbonate and edta, respectively [47], 0.33 and 0.86 mmol g À1 for Pb 2+ sorption by chloride-containing Mg-Al-LDHs [48,49] and between 0.78 and 2.50 mmol g À1 for Cu 2+ sorption by chloride intercalated LDHs either [42,50]. In all cases sorption was assigned to a hydroxide precipitation mechanism, except for the case of Cd 2+ , which only reaches significant sorption capacity when complexation mechanism is incorporated by intercalating the solid with edta.…”

Plasticized Poly(vinyl alcohol)/Starch as a Nutrient Delivery System for Macro and Micronutrients

“…The thinning band and displacement from 1038 to 1024 cm –1 in the Micromaterial were due to a predominance of starch aspects in the region that corresponds to the C–O vibration of the PVA amorphous chain . The 600 cm –1 band corresponds to the SO 4 2– group, the micronutrient source from used salts . For Micro afterTDR , the spectrum did not present bands related to the presence of SO 4 2– , which could mean (i) the sulfate was released; (ii) the remaining amount of sulfate was insufficient to appear in the spectra.…”

“…56 The 600 cm −1 band corresponds to the SO 4 2− group, the micronutrient source from used salts. 57 For Micro afterTDR , the spectrum did not present bands related to the presence of SO 4 2− , which could mean (i) the sulfate was released; (ii) the remaining amount of sulfate was insufficient to appear in the spectra.…”

Adsorption Applications of Acid Blue 7 on Mg/Al Layered Double Oxides and Mechanism Study

“…作为制备的 LDHs 有如下几个特点: (1)主体层板 的化学组成可调变; (2)层间客体阴离子的种类和数量可 调变; (3)粒径尺寸和分布可调控. 研究发现, 水滑石在 一定温度下焙烧, 可以生成具有高比表面积以及"结构 记忆效应"的双金属复合氧化物(LDO), LDO 在一定的 湿度(或水)和 CO 2 (或碳酸盐)条件下, 可以吸收溶液中 的阴离子恢复层板结构, 从而形成 LDHs [3,4] . [12] .…”