A situ co-precipitation method to prepare magnetic PMDA modified sugarcane bagasse and its application for competitive adsorption of methylene blue and basic magenta.

Magnetic pyromellitic dianhydride (PMDA) modified sugarcane bagasse (SCB) was prepared by a situ co-precipitation method. Results showed that the magnetic modified SCB could be recycled easily by an applied magnetic field. Adsorption capacities of the magnetic sorbent for cationic dyes: methylene blue and basic magenta were 315.5 and 304.9mgg(-1), respectively. Competitive adsorption in the binary system showed that concentration percentages (C(P)) and initial concentration (C(0)) both had good linear relationship with adsorption capacities of the magnetic sorbent (q(e)(')) in the investigated range. The linear equations between C(P) and q(e)(') almost did not affect by the variation of total initial concentration of the dyes (C(T)), whereas that between C(0) and q(e)(') changed greatly with it. C(P) was the main factor that impacted q(e)(') in the binary competitive adsorption system. Similar linear equations between C(P) and q(e)(') demonstrated that the magnetic sorbent had similar adsorption affinity toward the two dyes.