Advanced Treatment of Coking Wastewater with Inorganic/Organic Composite Modified Bentonite

Through the organic and inorganic composite modification of the calcium-base bentonite from Heishan of Liaoning Province,an efficient and inexpensive adsorbent was developed and used in advanced treatment of coking wastewater. The influences of factors such as bentonite size,reaction temperature,adsorbent dosage,pH value,reaction time and so on were investigated. The results show that the bentonite modified with Al2(SO4)3 of 5 g/L and CTMAB of 0.02 mol/L can remove the ammonia nitrogen and COD from the secondary effluent. Under the conditions of the dosage of 40 g/L,time of 30 min,temperature of 25 ℃ and pH value of 9,the removal rates of ammonia nitrogen and COD can reach 75% and 47% respectively. The effluent concentrations of ammonia nitrogen and COD can be reduced to less than 25 mg/L and 150 mg/L respectively. The developed adsorbent creates favorable condition for reclamation and reuse of coking wastewater.