| With the development of China’s industrialization and urbanization, heavy metal ions and organic pollutants has been causing serious contamination to air, water and soil in environmental media. Therefore, the study of novel water treatment material to deal with these pollutants has become the focus of scholars both at home and abroad. Due to the special structure of the clay rectorite, it was chosen as substrate to develop a series of multi-functional water treatment material.Based on previous studies, this paper starts from the current practical problem of rectorite application in environment. Rectorite used as basic absorbing material, modified by the organic, inorganic functions to prepare a series of composite clay rectorite material with multi-function of adsorption-flocculation-the degradation, reached the properties to improve and expand rectorite composite materials. The studies of this paper are as follows:(1) Chitosan/rectorite (CS/REC) organic polymer composite adsorbent was prepared and the process was optimized, the structure of adsorption materials was characterized. The results show that the particle size of nano rectorite/chitosan composite is 5 nm-48 nm, the surface area is 25.6 m2/g, and the average pore diameter is 16.8 nm. By static adsorption experiment, the adsorption data of nano rectorite/chitosan composite on metal ions Pb2+, Cu2+ and Cd2+ can fit Langmuir isotherm model well. The maximum adsorption capacities of Pb2+, Cu2+ and Cd2+ are 50.76 mg/g,41.32 mg/g and 32.47 mg/g respectively, adsorption kinetics of Pb2+, Cu2+ and Cd2+ agrees with pseudo second order kinetics model.(2) Nano magnetic rectorite (MREC), magnetic rectorite/chitosan (MREC/CS), magnetic rectorite/carboxymethyl chitosan (MREC/CMC) composite were prepared, the structure of adsorption materials were characterized. Different impact factors of rectorite and three magnetic materials adsorption properties on Pb2+, Zn2+ and Cd2+ were examined. The results show that the particle size of magnetic nano-composite MREC, MREC/CS, MREC/CMC are in the range of 5 nm-20 nm,15 nm-50 nm and 15 nm-60 nm, and their surface area are 15.6 m2/g,32.6 m2/g and 28.9 m2/g respectively. The adsorption of rectorite, MREC, MREC/CS, MREC/CMC on Pb2+, Zn2+ and Cd2+ in aqueous solution also agrees with pseudo second order kinetics model. The adsorption of rectorite-based composite materials on Pb2+, Zn2+and Cd2+ has adsorption rate sequence:MREC/CS, MREC/CMC, MREC, REC. The adsoption capacity of rectorite-based composite materials on Pb+: MREC/CS, MREC/CMC, REC/CS, MREC, REC.(3) Rectorite/polysilicate ferro-aluminum sulfate (REC/PSFA) composite was prepared, the structure and interaction of composite were analyzed and the adsorption and flocculation properties of nano-composite on oily wastewater and methylene blue were investigated. The results show that rectorite/polysilicate ferro-aluminum sulfate (REC/PSFA) is a special composite material with a network nano-rod structure. The length of the nano-rod is 20 nm-100 nm, the diameter is 3 nm-5 nm, and rectorite/polysilicate ferro-aluminum sulfate has good thermal stability. When the dosage of sulfuric acid is 230 mL, rectorite content is 33%, the removal of the nano composite material on oil content and chemical oxygen demand (COD) reached 87.2% and 92.6%, respectively. Under the same condition, the adsorption order is PSFA/REC, PSFA, REC.When initial concentration of methylene blue is 20 mg/L, the dosage of three adsorption and flocculation materials is 150 mg/L, pH 8, the adsorption, flocculation and removal effect of PSFA/REC nano-composite on methylene blue reach 91%. The decolorization performance of three adsorption-flocculation materials on methylene blue is in the order:PSFA/REC, REC, PSFA.(4) Zinc Oxide/Rectorite (ZnO/REC) nano-composite adsorption photocatalyst material was prepared, the structure and morphology were characterized and the preparation process was optimized. The results show that the obtained Zinc Oxide/Rectorite is nano-composite, the size ranges in 10 nm-25 nm, nano-ZnO size is 20 nm-50 nm, surface area is 16.772 m2/g, which increase 3.165 times compared with pure ZnO. The best performance condition for the removal of methylene blue is when the dosage is 0.9 g/L, the initial concentration of methylene blue is 5 mg/L, pH solution is 6.0.The adsorption of Zinc Oxide/Rectorite nano-composite and Zinc Oxide on methylene blue fit Langumiur isotherm model, the saturated adsorption capacity qm of ZnO/REC and ZnO were 31.056 mg/g and 20.41 mg/g, respectively. The Gibbs free energy of ZnO/REC nano-composite and ZnO is -18.425 KJ·mol-1 and -16.556 KJ·mol-1, respectively. So the nano-composite ZnO/REC has better photocatalysts adsoption performance on methylene blue than that of Nano ZnO.The ZnO/REC and ZnO on Methylene Blue of aqueous solution Photocatalytic reaction rate is 0.1238 min-1 and 0.0823 min-1 respectively, and it has certain stability and recycling. Detection and analysis of the methylene blue of aqueous solution photocatalytic degradation product, a number of phenols, alcohols, acids and esters and other substances, and inferred that the photocatalytic degradation methylene blue of aqueous micro-kinetic mechanism. |
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