A column study on Cu (II) adsorption from synthetic solutions using phyto-mineral hybrid adsorbents: RSM optimization, regression modeling and isotherm studies

Abstract

Herein we report a novel approach to synthesize hybrid adsorbents using moringa oleifera and zeolite. Three variants were prepared using zeolite mass fractions % of 0.25 %, 0.5 % and 0.75 % respectively. The hybrid adsorbents were investigated for Cu (II) removal from synthetic wastewater using fixed bed column. The lab-scale fixed bed column was designed for Cu (II) removal and optimized using Response Surface Methodology (RSM). The variable parameters included bed height, flow rate, metallic concentration and zeolite mass fraction %. As per results, higher zeolite mass fraction resulted in higher Cu (II) removal. Similarly, the higher bed height increased the removal % of Cu (II). On the other hand, both higher flow rate and metallic concentrations resulted in a declined removal. The highest removal of Cu (II) ions was indicated by hybrid adsorbent with zeolite mass fraction of 0.75 % with 96 % at 1 mL/min flow rate, bed height of 3 cm and metallic concentration of 5 ppm respectively. The maximum adsorption capacities (Qm) indicated by hybrid adsorbents were 19 mg/g (0.25 % Mass Fraction Z), 21.5 mg/g (0.5 % Mass Faction Z) and 24.5 mg/g (0.75 % Mass Fraction Z). The adsorption data best fitted Langmuir Isotherm with R2 value of 0.99 for all variants. When the adsorption data was analyzed using isotherms, data by all three variants best fitted Langmuir isotherm with R2 values of 0.99 for all the variants. Conclusively, higher mass fraction % of zeolite enhanced the removal capacity of Phyto-mineral hybrid adsorbents for Cu (II), whereas higher flow rates and metal concentrations resulted in a declined adsorption of the respective metal ions.