Mesoporous polymetallic silicate derived from naturally abundant mixed clay: A potential robust adsorbent for removal of cationic dye and antibiotic

Abstract Mesoporous polymetallic silicate adsorbents with superior adsorption capability towards methylene blue (MB) and tetracycline (TC) were synthesized by a simple one-pot reaction process. The mesoporous adsorbent was formed from the conversion of the mineral components in natural clay and the simultaneous incorporation of Cu(II) without using additional template agent. The specific surface areas of the adsorbent (348.13 m2/g) reached 5.9 times that of original clay. The optimal adsorbent can adsorb rapidly 289.46 mg/g of MB and 415.56 mg/g of TC; and can remove 99.9% of MB (adsorbent dosage, 1 g/L) and 93.9% of TC (adsorbent dosage, 3 g/L) from 200 mg/L of the original solution. The superior adsorption is resulting from the synergistic action of electrostatic and hydrogen-bonding interaction between negatively charged adsorbent and positively charged MB or TC, the chemical interaction between active -Si-O− groups and MB or TC and the complexing of MB or TC with metallic sites.