Preparation Of Cellulose/Diatomite Beads And The Studies Of Adsorption Processes

A green-based absorbent combined with alkali-treated diatomite was prepared. An appropriate amount of calcium carbonate was added to increase pore structure under an acidic condition. The synthesized cellulose/diatomite beads were characterized with FT-IR, SEM, TGA,1HNMR, BET and so on. The degree of carboxylation of modified cellulose/diatomite beads was quantified using titration methods (Colloid Titration and Acid-base titration).The removal of basic dyes (methylene blue and methyl violet) and lead ions (Pb2+) from aqueous solution were systematically investigated. The influence of pH, shaking time, and temperature on the removal process was identified. The dynamic adsorption processes indicated that the optimum conditions for basic dyes and heavy metals were30℃, pH7.0,300min for MB,30℃, pH6.5,200min for MV and30℃, pH6.0,90min for Pb2+, respectively.The adsorption kinetics and adsorption isotherms of different adsorbates were also investigated. The results indicated that the modified cellulose/diatomite beads had a strong adsorption capacity toward dyes and heavy metal ions, the experimental kinetic data fit the pseudo-second order model very well. Moreover, the adsorption process for Pb2+was better described by the Langmuir isotherm model. The maximum adsorption capacity was118mg/g for MB,62.11mg/g for MV and39.54mg/g for Pb2+under optimum conditions, respectively.Desorption experiments were carried on using1M HC1as the eluent, the removal rate (%) of different adsorbates were substantially unchanged after reusing three times, indicated that the MCDBs were renewable and green absorbent for wastewater removal.