Selective ultrasound enhanced removal of anionic dyes from binary mixture using multivariate calibration and central composite design modeling by positively charged hyper branched ammonium functionalized magnetic graphene oxide

Covalently bonded third generation dendrimer to magnetized graphene oxide nanosheets (DMGO), with high adsorption capacity, were synthesized and efficiently used for simultaneous removal of reactive red 195 (RR) and reactive yellow 145 (RY) dyes. The important parameters like initial concentrations of dyes, sorbent mass and sonication time was optimized using central composite design (CCD) combined with response surface methodology (RSM). Because of the severe overlapping spectra of the dyes, at each removal condition, the dyes concentration were obtained by application partial least squares (PLS) as a powerful multivariate calibration method. The optimized parameters were found to be 12.5 min sonication time, 15 mg of sorbent, RR concentration 20.0 mg L-1 and RY concentration 45.0 mg L-1. These optimal condition were achieved the removal percentage of 99.20 and 98.80 % for RR and RY, respectively. In order to evaluate sorption performance, isotherms and kinetics studies were carried out under batch adsorption experiments. The adsorption process follows pseudo-second order reaction kinetic, as well as Langmuir isotherm. The results showed that the sorbent had a maximum adsorption capacity of 53.76 and 73.53 mg g-1 corresponds to RR and RY, respectively.