Abstract:

 In order to understand adsorption capacity of cocoon to chromium in wastewater, cocoon shell, which washed cocoon shell and citric acid modified cocoon shell were used to adsorb chromium in simulated wastewater, and the adsorption effect was tested with adsorption rate and unit adsorption capacity. The results show that the effects of absorbing chromium using untreated cocoon shell is poor, and that using washed cocoon shell is better; and the effects of absorbing chromium using urea modified cocoon shell is inferior that using washed cocoon shell, and the of absorbing chromium using citric acid modified cocoon shell is slightly better that using washed cocoon shell. Under the conditions of temperature of  50 ℃, pHof 1, bath ratio of 1 : 50 , chromium of 60 μg/mL and adsorption time of 40 min, the adsorption rate of washed cocoon shell was of 73.79%, and the unit adsorption capacity thereof was 2.2 mg/g. Under the conditions of temperature of 30 ℃,  pH of 1, bath ratio 1 : 50 , chromium concentration of 40 μg/mL and adsorption time of 120 min, the adsorption rate of citric acid modified cocoon shell was of 81.29%, and the rnit adsorption capacity of 1.63 mg/g.

Key words: cocoon shell, chromium, adsorption rate, unit adsorption capacity