Removal of lead from aqueous solution using low-cost adsorbents from Apiaceae family

Adsorbents prepared from the Apiaceae family, namely parsley (PL), coriander (CR), and cilantro (CL), were used for lead (Pb(II)) removal from low-concentration aqueous solutions. Physical and chemical characterizations were carried out by the Brunauer-Emmett-Teller adsorption isotherm, scanning electron microscopy coupled with energy dispersive X-ray analysis, and Fourier transform infrared (FTIR) spectra analysis. Batch experiments were conducted to study the effect of biomass dosage, pH, contact time, agitation speed, and initial lead concentrations. The maximum biosorption of Pb(II) was approximately 89% with 1.0 g/L biomass under an optimum pH of 5 with 2 mg/L initial lead concentration for the three selected adsorbents. The lead removal rate increased with an increase of dosage, speed of rotation, and contact time, while it decreased with a pH greater than 5, and increased initial Pb(II) concentration. The maximum monolayer adsorption capacity of the PL, CR, and CL was 4.48, 2.94, and 3.87 mg/g, respectively. It was found that the Langmuir isotherm provides a good model to describe the adsorption process for PL, CR, and CL. The adsorption process obeyed a pseudo-second-order kinetic model in all cases. Due to its ease of use, local availability, low-cost, and good adsorption capacities, PL, CR, and CL can be used as effective adsorbents for Pb(II) removal from low-concentration aqueous solutions.