Optimization of Cr(VI) biosorption onto Aspergillus niger using 3-level Box-Behnken design: Equilibrium, kinetic, thermodynamic and regeneration studies

Abstract

Heavy metal biosorption is an efficient technology for the decontamination of metal from industrial waste water. The present study focused on exploration of Aspergillus niger towards removal of Cr(VI) from aqueous solution. The influence of different experimental parameters—initial pH, adsorbent dose, initial concentration, contact time, shaking speed, temperature, and their combined effect during Cr(VI) adsorption—was investigated by means of response surface methodology based on four factorial Box–Behnken experimental design. Optimized values of initial Cr(VI) concentration, pH, adsorbent dose, and contact time were found as 33.33 mg/L, 4.6, 1.0 g/L, and 48.45 min, respectively. A. niger showed the highest adsorption capacity 11.792 mg/g at initial pH 2.0. Equilibrium data fitted well to the Temkin and Freundlich isotherms. Cr(VI) biosorption showed Pseudo-second order rate kinetics. The activation energy of the adsorption was estimated as 2.9 × 10−3 kJ/mol. Thermodynamics properties of the Cr(VI) biosorption was spontaneous in nature. Desorption study showed that nearly 94% of the Cr(VI) adsorbed on A. niger could be desorbed using 0.5 M EDTA.

The sorption of cationic and anionic heavy metal species on the biosorbent of Aspergillus terreus: Isotherm, kinetics studies

“…This increase in porosity certainly leads to an increase in the adsorption capacity of the adsorbents. Also, the adsorbent has some heterogeneity which is supposed to be the active site for metal binding . Figure c,d shows the adsorbent surface status after adsorption of the Cr (VI) and Cd.…”

“…As seen, the surface and holes of the biomass are well occupied by two metals, so the biomass has had an acceptable adsorption efficiency. Also, SEM pictures also revealed that the surface of fungal biomass ( A. terreus ) is flattened after Cr (VI) and Cd adsorption . As seen in Figure , determination of the surface‐active functional groups on the Aspergillus terreus fungus biomass was performed by FTIR analysis using FTIR spectrophotometer.…”

“…Since the concentration of Cd and Cr (VI) in industrial wastewater is reported to be up to 200 mg/L, thus concentrations of 20, 40, 60, 80, 100, and 120 mg/L were prepared to investigate the effect of the initial concentration of the pollutant on adsorption percentage. 26 In addition, the effects of pH in the range of 3-8 pH (which was adjusted by 1 N HCl and NaOH solution and measured with pH-meter 765), the contact time (15,30,45,60,90, and 120 min), and the dose of adsorbent (0.1, 0.2, 0.5, 1, and 2 g per 100 mL) were studied. 27 Finally, after the adsorption process, the separation of the adsorbent from the samples was performed by centrifuging (RPM4000 model 19594) at 2,500 rpm, and the concentration of the remaining heavy metals was determined using an atomic absorption device (Varian model).…”

Modeling and optimization of chromium adsorption onto clay using response surface methodology, artificial neural network, and equilibrium isotherm models

“…Chromium is known as one of the most hazardous heavy metals and is a serious threat . It is used in different industries such as: electroplating, leather tanning, steel industry, textile dyeing, paint and pigment formulation, refractory materials, mining, wood preservation, cement, alloys, photographic materials, and is discharged in the environment through their wastes . Trivalent and hexavalent chromium are the most common forms in the environment .…”

“…Considering the points mentioned above, recovery or removal of heavy metals from aqueous media is one of the top priorities. So, researches are still performed on procedures that are both economical and eco‐friendly . Recently, different techniques have been improved for the treatment of heavy metal containing wastewaters, to decrease the wastewaters' quantity and increase the treated wastewaters' quality .…”