Biocomposite application for the phosphate ions removal in aqueous medium

Mango stone biocomposite efficiency for the removal of phosphate ions (PO43-) from aqueous solution was investigated as a function of pH (2-8), biocomposite dose (0.05-0.40 g/100 mL solution), contact time (5-120 min), initial PO43- ions concentration (20-800 mg/L) and temperature (33-61 degrees C). Maximum PO43- ions removal was achieved at pH 2, biocomposite dose 0.3 g, contact time 90 min and initial PO43- ions concentration 200 mg/L. At optimized conditions, up to 95 mg/g PO43- adsorption was achieved. Biocomposite pre-treatment with surfactants (SDS, Tween-80, C-TAB, VIM and Surf excel) were also investigated and it was observed that surfactants pre-treatments decreased the adsorption capacity of the biocomposite. Thermodynamic study (Delta G degrees, Delta H degrees and Delta S degrees) revealed that PO43- adsorption process onto biocomposite was spontaneous and endothermic in nature. Adsorption data fitted well to the Freundlich isotherm and pseudo-second-order kinetic model. Adsorbed PO43- was successfully desorbed using 1.0 M NaOH solution. Results revealed that biocomposite adsorbed PO43-,which could possibly be used for the adsorption of PO43- efficiently from wastewater. (C) 2017 Brazilian Metallurgical, Materials and Mining Association. Published by Elsevier Editora Ltda.