Role of synthesis process variables on magnetic functionality, thermal stability, and tetracycline adsorption by magnetic starch nanocomposite

Abstract

Poor understanding and possible control of influence of synthesis variables on intrinsic properties/characteristics, has negatively impacted full utilization of magnetic polymer nanocomposite in potential applications. This study was therefore designed to investigate the synthesis variables that control the magnetic functionality, thermal stability, yield and tetracycline adsorption by magnetic starch nanocomposite. Subsequent upon this, the study is set to further develop a goal oriented multiple response optimization (GOMRO) approach for simultaneous control of these intrinsic properties and their potential applications. Magnetic starch nanocomposite was synthesized by in-situ co-precipitation of Fe2+ and Fe3+ in the presence of soluble starch, and characterized with FTIR, TEM, XRF, and TGA/DTA. The characterization tests confirmed that magnetic starch nanocomposite was successfully synthesized. Model evaluation parameters showed that quadratic model adequately (r2 > 0.98) described the experimental data for all the studied properties and tetracycline adsorption. Variance analysis of influence of quantity of starch gave F-values of 695.95, 22.43, and 134.89 for magnetic functionality, thermal stability, and tetracycline adsorption, respectively, while Prob > F gave value of <0.0001, in each case. These data indicated that quantity of starch and ammonia volume were the dominant factors controlling the studied properties and tetracycline adsorption. For the first time, response surface methodology (RSM) was successfully applied in elucidating the adsorption interaction mechanism, as both experimental and RSM trend confirmed that π-cation interaction was the dominant interaction mechanism for tetracycline adsorption by magnetic starch nanocomposite. Besides controlling the process cost from the yield, the GOMRO approach opened additional degree of freedom on cost control by creating opportunity for manipulating the quantities of reactants for achieving a set goal.