Development and analysis of diethylaminoethyl silica-based adsorption column for removing antibiotic resistance genes from wastewater

Abstract

The current study investigates the efficiency of diethyl aminoethyl silica gel (DEAE-Si) based adsorption column for removing antibiotic resistance genes from secondary treated wastewater. Various column parameters like packing shape, packing size, bed height, and flowrate were analyzed to study their effect and optimize the column performance. The adsorption capacity of the column varied in range of ∼4.5 to 7.8 μg/g of DNA adsorbed. For regular packing of spherical shape, 3 mm–5 mm beads size, 8 cm column height, and flow rate of 0.5 mL/min. Adsorption capacity of 6.23 μg/g with 20 h of break through time and 36 h of saturation time was attained. The column regeneration was performed using NaCl solution at pH 8.5 ± 0.5. High removal efficiency of around 90 % up to 3 regeneration cycles, 75 % for 4th regeneration cycle, and >50 % for 5th regeneration cycle was attained. For practical understanding and to check how the column would perform for increased volumes of wastewater 10 times larger sized column was analyzed in simulated and real secondary treated wastewater matrix. The adsorption capacity attained using large column was around 4.65 μg/g at higher flowrate of 5 mL/min. and constant empty bed contact time resulting in treating up to 17.1 L of wastewater. The overall performance of large column was satisfactory and comparable with the test column in simulated wastewater matrix. >80 % removal efficiency of ARGs of different size in real secondary treated wastewater matrix was achieved on maintaining low flowrate.