Adsorption of malachite green in a fixed-bed columns by Thiourea modified poly(acrylonitrile-co-acrylic acid)

Abstract

Thiourea-modified poly(acrylonitrile-co-acrylic acid) (TU-poly(AN-co-AA)) polymeric adsorbent was synthesized and characterized with Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM) and Zetasizer. Adsorptive removal of cationic malachite green (MG) dye from aqueous solution in a continuous TU-poly(AN-coAA) packed-bed column was studied. The influences of solution pH (2-9), inlet MG concentration (25-80 mg/L), bed depth (4-8 cm) and linear flow rate (1.5-5.0 mL/min) were investigated via assessment of the column breakthrough curves. Low pH and short bed depth, high MG concentration and flow rate led to early breakthrough of MG. According to correlation coefficients (R2) and sum of the squares of the errors (SSE) values, Thomas and Yoon-Nelson dynamic models are more suitable to describe the column experimental data compared to the Bohart-Adams model. TU-poly(AN-co-AA) exhibited effective separation of MG from the liquid phase and displayed high adsorption capacities after five regeneration cycles.