Adsorption studies of some phenol derivatives onto Ag-cuttlebone nanobiocomposite: modeling of process by response surface methodology

Abstract

A novel nanobiocomposite in the role of adsorbent was prepared by mixing silver (Ag) nanoparticles with cuttlebone (CB) and was characterized by UV–Vis, DLS, XRF, EDX, FE-SEM and BET analysis. Modeling and optimization of simultaneous removal of 4-nitrophenol and 4-chloro-2-nitrophenol in binary solution by adsorption onto prepared adsorbent (Ag–CB) was studied using response surface methodology (RSM). The adsorption of phenols onto Ag–CB reached equilibrium within 25 min. The removal efficiency increased with increment of Ag–CB dosage (1–5 g L−1) and contact time (5–25 min), whereas it decreased with increasing the solution pH (3–11) and the initial concentration of phenols (5–25 mg L−1). The removal efficiency of phenols under optimum conditions (initial phenols concentration of 10 mg L−1, Ag–CB dosage of 4 g L−1, pH of 5 and contact time of 20 min) was 86.41%. Polymath software was used to draw nonlinear isotherm and kinetics curves. The nonlinear regression methods revealed that the adsorption data can be well interpreted by Freundlich isotherm model (K F = 0.30 [(mg g−1)(L mg−1)]1/0.66; n = 0.66) and Ho’s pseudo-second order kinetics equation (k 2 = 0.17 g mg−1 min−1). Thermodynamic parameters declared that adsorption process was exothermic and nonspontaneous in the temperature range of 25–45 °C.