Biotemplated synthesis of mesoporous silica for doxycycline removal. Effect of pH, temperature, ionic strength and Ca2+ concentration on the adsorption behaviour

摘要: Abstract Mesoporous silica (SiO2) materials were synthesized in acidic media, using tetraethyl orthosilicate as precursor and the water-soluble biopolymer hydroethyl starch (HES) template, order to evaluate effect of temperature synthesis on morphology pore structure materials. The results show that mentioned parameters can be tuned by changing temperature, i.e., from slices with worm-like mesopores around 5 nm microporous lamellas when increases 60 °C 100 °C, respectively. changes are attributed a (partial) degradation template hinders gel formation disturbs its interaction species through H-bonds formations and/or electrostatic interactions. solids evaluated adsorbent antibiotic doxycycline (DC) at several values pH, ionic strength Ca2+ concentration. adsorption DC strongly pH decrease due attractions H-bond between functional groups active sites. presence calcium ions pH > 4.4 ternary DC–Ca2+–SiO2 complexes calcium-bridging. However, concentrations higher than 10−3 M cause precipitation 7 or higher. analysis thermodynamic suggests SiO2 is exothermic spontaneous nature. tetracycline capacity material was also discussed.