Extraction and preconcentration of nickel, cadmium, cobalt, and lead cations using dispersive solid phase extraction performed in a narrow-bore tube

Preconcentrations of Pb(II), Ni(II) and Zn(II) by solid phase bio-extractor using thermophilic Bacillus subtilis loaded multiwalled carbon nanotube biosorbent

An alternative biotechnological solid phase bio-extraction (SPE) method was developed. Bacillus subtilis loaded multiwalled carbon nanotube was designed and used as biosorbent for the preconcentrations of Pb(II), Ni(II), and Zn(II). The experimental parameters such as sample flow rate, pH of sample solution, amounts of Bacillus subtilis and multiwalled carbon nanotube, volume of sample solution and reusability of column which affects the analytical characteristics of the SPE method were investigated in details. Surface structures were examined by using FTIR, SEM. The best pH was determined as 5.0 and the percentages recoveries of Zn(II), Ni(II), and Pb(II) were determined as 99.1%, 98.7%, and 96.2%, respectively, at a flow rate of 3 mL/min. In this study, in which the profitable sample volume was determined as 400 mL and the amount of multiwalled carbon nanotube (MWCNT) as 50 mg. It was also observed that the column had a significant potential to preconcentrate Zn(II), Ni(II), and Pb(II) even after 25 reuses. The biosorption capacities for Zn(II), Ni(II) and Pb(II) were calculated as 39.67 mg/g, 45.98 mg/g and 51.34 mg/g respectively. The LOD values were calculated as 0.024 ng/mL for Pb(II), 0.029 ng/mL for Ni(II), and 0.019 ng/mL for Zn(II). The linear range was detected as 0.25-25 ng/mL. The concentrations of Pb(II), Ni(II), and Zn(II) in a variety of real food samples were determined by using developed method after application of certified reference sample.

Preconcentrations of Ni(II) and Pb(II) from water and food samples by solid-phase extraction using Pleurotus ostreatus immobilized iron oxide nanoparticles

The present study explores the biosorption potential of Pleurotus ostreatus immobilized magnetic iron oxide nanoparticles for solid-phase extractions of Ni(II) and Pb(II) ions from the water and food samples. It was characterized using FTIR, FE-SEM/EDX before and after analyte ions biosorption. Important operational parameters including the effect of initial pH, the flow rate of the sample solution and volume, amount of biomass and support material, interfering ions, best eluent, column reusability were studied. The biosorption capacities of fungus immobilized iron oxide nanoparticles were found as 28.6 and 32.1 mg g^-1 for Ni(II) and Pb(II), respectively. The limit of detection (LOD) and limit of quantitation (LOQ) were achieved as 0.019 and 0.062 ng mL^-1 for Ni(II), 0.041 and 0.14 ng mL^-1 for Pb(II), respectively. The proposed method was validated by applying to certified reference materials and successfully applied for the preconcentrations of Ni(II) and Pb(II) ions from water and food samples by ICP-OES.