کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5749304 1619150 2017 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Reducement of cadmium adsorption on clay minerals by the presence of dissolved organic matter from animal manure
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم محیط زیست شیمی زیست محیطی
پیش نمایش صفحه اول مقاله
Reducement of cadmium adsorption on clay minerals by the presence of dissolved organic matter from animal manure
چکیده انگلیسی


- The presence of CM-DOM greatly reduces Cd2+ sorption on bentonite and zeolite.
- The presence of Cd2+ significantly promotes CM-DOM sorption on bentonite.
- The two clay mineral/CM-DOM/Cd2+ systems exhibit different ternary structures.
- The decrease in Cd2+ sorption is mainly attributable to mineral-adsorbed CM-DOM.
- Decrease mechanisms for bentonite and zeolite are discussed based on SEM study.

Clay minerals are the most popular adsorbents/amendments for immobilizing heavy metals in contaminated soils, but the dissolved organic matter (DOM) in soil environment would potentially affect the adsorption/immobilization capacity of clay minerals for heavy metals. In this study, the effects of DOM derived from chicken manure (CM) on the adsorption of cadmium (Cd2+) on two clay minerals, bentonite and zeolite, were investigated. The equilibrium data for Cd2+ sorption in the absence or presence of CM-DOM could be well-fitted to the Langmuir equation (R2 > 0.97). The presence of CM-DOM in the aqueous solution was found to greatly reduce the adsorption capacity of both minerals for Cd2+, in particular zeolite, and the percentage decreases for Cd2+ sorption increased with increasing concentrations of Cd2+ as well as CM-DOM in aqueous solutions. The adsorption of CM-DOM on zeolite was greater than that on bentonite in the absence of Cd2+, however, a sharp increase was observed for CM-DOM sorption on bentonite with increasing Cd2+ concentrations but little change for that on zeolite, which can be attributed to the different ternary structures on mineral surface. The CM-DOM modified clay minerals were utilized to investigate the effect of mineral-adsorbed CM-DOM on Cd2+ sorption. The adsorbed form was found to inhibit Cd2+ sorption, and further calculation suggested it primarily responsible for the overall decrease in Cd2+ sorption on clay minerals in the presence of CM-DOM in aqueous solutions. An investigation for the mineral surface morphology suggested that the mineral-adsorbed CM-DOM decreased Cd2+ sorption on bentonite mainly through barrier effect, while in the case of zeolite, it was the combination of active sites occupation and barrier effect. These results can serve as a guide for evaluating the performance of clay minerals in immobilizing heavy metals when animal manure is present in contaminated soils.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Environmental Pollution - Volume 223, April 2017, Pages 247-254
نویسندگان
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