A Basic Study On Preparation Method Of Nano Fe/Ni Bimetallic Particles And Its Removal Capacity For CAHs From Water

Chlorinated aliphatic hydrocarbons (CAHs) as chemical raw materials and organic solvents, are widely used in chemical, leather, pharmaceutical and electronics industries. As a result of the leakage or injetion occur in the process and industrial direct emissions, CAHs results in the critical contamination of soil and groundwater environments. The objective of this study is to evaluate the effectiveness of removing CAHs from groundwater with nano-scale Fe/Ni (iron/nickel) particles. Liquid phase chemical reduction coprecipitation method, chosen 42% polyethylene glycol as dispersing agent and freeze drying as the dring technique, was employed for the preparation of nano-Fe/Ni bimetallic materials. The Fe/Ni particles, with average size of 20nm, have amorphous nano-alloy structure. The results of batch CAHs degradation experiments by nano Fe/Ni with different Ni content shown that, for 1,1,1-TCA and PCE, the optimum Ni content is 11%, while nano Fe/Ni with 6% Ni content has the best removal capacity for TCE. This phenomenon implies that the higher content of Ni metal catalyst doesn't mean the better performance for CAHs removal. As the dosage increases, the nano-Fe/Ni particles will reduce TCE more quickly with higher removal rate. When 1,1,1-TCA and TCE co-exist in the water, slower reduction was observed with lower removal rate for each CAH. Ca2+, Mg+, Na+,SO42-,NO3-, Cl-, and methanol were found have negative effects on 1,1,1-TCA and TCE degradation, while the effect of humic acid sodium is constituted of competitive adsorption and transmission of electron. The CAHs removal kinetics by nano Fe/Ni consists with the pseudo-first order kinetics model.