In this paper, functionalized sodium alginate hydrogel (FSAH) was prepared to efficiently adsorb heavy metals and dyes. Hydrazide-functionalized sodium alginate (SA) prepared hydrazone groups to selectively capture heavy metals (Pb2+, Cd2+, and Cu2+), and another functional group (dopamine grafting), serves as sites for adsorption methylene blue (MB), malachite green (MG), crystal violet (CV). Thermodynamic parameters of adsorption indicated that the adsorption process is endothermic and spontaneous. The heavy metals adsorption by FSAH was physical adsorption mainly due to ΔHθ < 40 kJ/mol, and the adsorption of cationic dyes fitted with the Langmuir models, which indicated that the monolayer adsorption is dominated by hydrogen bonds, electrostatic interactions, and π-π interactions. Moreover, the adsorption efficiency maintained above 70% after five adsorption-desorption cycles. To sum up, FSAH has great application prospect.
This essay studies a novel environment-friendly synthesis method for the high purity micron iron phosphate. Compared with traditional synthesis method, this new method can greatly reduce the amount of industrial sewage, hence it is an environment-friendly production technology which can effectively improve the products’ purity, structure stability and morphological consistency. This new method includes two-step reactions: first, phosphoric acid, iron powder and hydrogen peroxide are used as raw materials to obtain iron phosphate dihydrate intermediate, which is then calcined at high temperature to obtain anhydrous iron phosphate. The results show that the iron phosphate prepared for this new method is a hexagonal system-structured iron orthophosphate with high purity and without any impurities, exhibiting a regular and primary spherical particle morphology, at the average size of 3.096μm in particle and the specific surface area reaching 39.1765 m2 g−1. With these excellent characteristics, it has better application potentials in the field of electrode material preparation. The electrochemical performance of lithium iron phosphate anode materials synthesized with it as the precursor is superior to those synthesized with the iron phosphate prepared by the traditional method as precursor. The first specific capacity of discharge at 0.5C and 10C can be as high as 154.3989 or 102.9326 mAh g−1, increasing by 2.74% and 8.03%, respectively.
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