Study on adsorption of Cd~(2+) by modified bamboo charcoal

摘要

Modified bamboo charcoal was made by immersion with Nitric acid and heating at high temperatures. This paper compared the adsorption properties before and after modified bamboo charcoal which were used to treat the Cd~(2+) solution. The influencing factors such as solution pH, adsorption time, charcoal dosage, initial Cd~(2+) concentration, temperature were investigated. The results show that modified bamboo charcoal made by immersion with Nitric acid and heating at high temperatures improves the adsorption efficiency. The equilibrium of adsorption capacity is 6.65mg/g. Adding 15 g modified bamboo charcoal in every 1L Cd~(2+) solution, the removing rate of Cd~(2+) is above 99% after adsorbed 60min under pH from 4 to 8. The adsorption Cd~(2+) process with modified bamboo charcoal accords with similar secondary dynamic model. Langmuir isotherm equation is more suitable than the Freundlich equation to describe the adsorption Cd~(2+) process with modified bamboo charcoal. The adsorption Cd~(2+) process is exothermic and physical adsorption.