Treatment of pollutants in high turbidity water by chitosan/sodium carboxymethyl cellulose complex coagulation system
Coagulation is a common process for surface water treatment due to its low cost and simple operation,but existing coagulants have the problem of a low removal rate of dissolved organic matter in surface water.In response to the widespread organic micro-pollution in surface waters in China,this paper designs a new process to remove pollutants by replacing traditional coagulants with complex coagulation flocs generated in situ by sodium chitosan/carboxymethylcellulose in water.Kaolinite and tetracycline hydrochloride were selected to simulate inorganic colloids and organic micro-pollutants in the Yellow River water respectively,and the initial turbidity and the amount of sodium chitosan/carboxymethylcellulose dosing were investigated on the removal efficiency and mechanism of the two types of pollutants,and the adsorption performance of the sludge produced after coagulation was further investigated.The experiments show that the turbidity removal rate of sodium chitosan/carboxymethyl cellulose was above 99％for different simulated polluted water and the best removal rates of tetracycline hydrochloride-kaolin and yellow river water-tetracycline hydrochloride were 40.02％and 56.72％respectively.Compared with PAC,the coagulation time of CS/CMC was shorter,the dosage was less and the coagulation effect was better.The sludge produced by co-precipitation of chitosan/sodium carboxymethylcellulose and kaolin was able to chemisorbed tetracycline hydrochloride in water with a maximum removal rate of 98.46％and a maximum adsorption capacity of 4.81 mg/g.This indicates that the flocs produced by coagulation were able to adsorb dissolved organic pollutants,enabling the sludge to be reused.The adsorption kinetic fitting shows that the adsorption of tetracycline hydrochloride by the sludge produced by co-precipitation of chitosan/sodium carboxy methylcellulose and kaolin clay was more in line with the quasi-secondary kinetic model.It is also consistent with the Freundlich adsorption isotherm model,which is a spontaneous and disordered heat absorption reaction.In conclusion,the chitosan/sodium carboxymethylcellulose co-collocation system has good potential to remove both inorganic and organic pollutants from surface water and the resulting sludge has good reuse value.
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万方数据
维普
