Effective removal of hexavalent chromium from water by sustainable nano-scaled waste avocado seeds: adsorption isotherm, thermodynamics, kinetics, and error function

Abstract In the current investigation, an efficient low-cost nano-scaled material was prepared from waste avocado seeds (NASs) and employed as a sustainable nanosorbent for removal of hexavalent chromium ions. The adsorption surface characteristics with respect to availability functional groups, basic component elements, structural properties NASs were achieved by different techniques. Analysis referred presence carbon oxygen contents providing 97.21%. particles homogenously identified ranged between 18.68 19.05 nm. impact various affecting parameters on ions elaborated optimized at pH 2.0, dose 10 mg, contact time 30 min, temperature 25 °C batch assay. Fifteen linear nonlinear modeling tests applied evaluate isotherms arranged in following fitting order: Tempkin < BET Dubinin-Radushkevich Generalized Halsey ˂ Flory–Huggins Freundlich Harkins–Jura Langmuir formulas Weber-van Vliet Radke–Prausnitz (II) (III) Fritz-Schlunder IV Baudu Multilayer V Toth 2 5 parameters. Linear pseudo -second-order models, intraparticle diffusion, Elovich models also scrutinized, both pore diffusion film similarly involved rate-limiting step. values ΔS° (0.21 kJ/mol), ΔH° (− 41.02 kJ/mol) ΔG° 28.30 − 19.97 high concentration (50 mg L −1 ) range 20–60 reflected disordering, spontaneously exothermic process. activation energy ( E confirmed include process potential application wastewater, seawater, tap water real aqueous matrices excellent percentage 98.44 98.86%. Based outlined results, one can deduce that performance efficiency temperature, low mass, accomplished evaluated NAS nanosorbent. Accordingly, investigated is recommended apply stress industrial wastewater treatment plants.