Abstract:

The authors researched the performance of the lowgrade diatomite adsorbing two organic dyes(Basic Pink and Direct Green B) and the effects of adsorbing time, adsorbent concentration, temperature and pH on the adsorption of the two organic dyes onto the diatomite. Moreover, the adsorption isotherms of the dyes on the diatomite were investigated. The results show that the adsorption of Basic Pink and Direct Green B onto the diatomite is a quick process, and the pseudosecondorder model provides a very good fitting for it. The temperature has little effect on the adsorption, but the acidic situation favors the process. Both Freundlich and Langmuir model can describe the adsorption well. The maximum adsorption capacity of Basic Pink onto diatomite, calculated by Langmuir model, is 104.1 mg/g, and that of the Direct Green B’s is 14.98 mg/g.

Key words: diatomite, organic dye, adsorption