Development of sustainable acid blue 113 dye adsorption system using nutraceutical industrial Tribulus terrestris spent

First-ever study was done using a low-cost Tribulus terrestris spent, a by-product of a nutraceutical industry as an effective biosorbent for removing acid blue 113 (AB113) from aqueous media. The effect of various factors such as pH, dye concentration, amount of adsorbent, particle size of adsorbent, contact time as also temperature on adsorption have been studied. Analysis of equilibrium data was done by using two number of two-parameter and six number of three-parameter isotherm models. Kinetic studies on adsorption were done using models like pseudo-first order and pseudo-second order. Webber–Morris and Dumwald–Wagner diffusion models helped to study diffusion. Determination and evaluation were also done for change in enthalpy (ΔH°), entropy (ΔS°), and Gibbs free energy (ΔG°) of adsorption system. Scanning electron microscopy, Fourier transform infrared spectroscopy and determination of point of zero-charge were carried out for surface characterization of the adsorbent. We have used a two-level fractional factorial experimental design approach and subsequently analysis of variance to define a statistically developed model from which we obtained values of above parameters which yielded maximum possible adsorption as 93.00 mg/g. The investigations proved that nutraceutical industrial T. terrestris spent is both cost-effective and an efficient biosorbent for the remediation of AB113 dye from aqueous system and textile industrial effluent.