fixed-bed column adsorption studies of methylene blue dye from an aqueous solution using silicon nitride adsorbent synthesized from sand and coffee husk wastes

This study presents a fixed-bed column adsorptive behavior of silicon nitride (si3n4) adsorbent for methylene blue dyes. the adsorbent was characterized using xrd and edx. effect of parameters such as influent concentrations, volumetric flow rate, and bed height for the column study are explored. the yoon-nelson, thomas, and adam-bohart models were used to predict breakthrough curves. the results showed α-si3n4 as the main adsorbent phase with silicon and nitrogen as the main elements. a column capacity (47.01 mg/g) was reported at optimal values of 4 ml/min, 7 cm and 50 mg/l. column dynamic modeling analysis revealed that thomas and yoon-nelson models best fitted the breakthrough curves than adam-bohart model. the column performance using spiked water samples athi showed that si3n4 adsorbent had a lower efficacy than in a model solution with the maximum column adsorption capacity of 38.92 ± 0.04 mg/g. the results revealed the potential of si3n4 adsorbent for decontamination of mb dyes from wastewater.