Decontamination of cationic and anionic dyes in single and binary mode from aqueous phase by mesoporous pulp waste

This work addresses the development of mesoporous pulp waste (MPW) and its application in sequestering of methylene blue (MB) and methyl orange (MO) from single and binary mode. Adsorption interactions of dyes onto MPW were investigated using N-2 adsorption/desorption isotherm, fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDS) P-XRD, thermo gravimetric analysis (TGA), pH(PZC), macro, and micro analyses. The developed MPW showed the presence of surface functional groups (OH, COOH groups), porous surface, higher BET surface area (1022.46 m(2)/g), pore volume (0.8338 cm(3)/g), and atomic percentage of carbon (54.93%) and oxygen (10.26%). The adsorptive uptake for both the dyes was computed in single (q(MB)=251.0 mg g(-1) and q(MO)=285.71 mg g(-1)) and binary mode (q(MB)=157.48 mg g(-1) and q(MO)=142.85 mg g(-1)). The adsorption mechanisms of MB and MO onto MPW were governed by hydrogen bonding and - interactions. The adsorption kinetics of MB and MO are better reflected by pseudo second-order for single and binary system with good correlations. Thermodynamic parameters exhibited the adsorption process to be spontaneous and endothermic in nature accompanying the increase of entropy (the driving force for adsorption). The regeneration of the adsorbent was performed with 0.1 M NaOH and CH3COOH (99-100%). The low cost of the developed MPW (USD 42.43 per kg) justify its utilization in the removal of dyes from aqueous phase. (c) 2014 American Institute of Chemical Engineers Environ Prog, 34: 724-735, 2015