Biosorptive removal of nitrophenol from aqueous solution using ZnCl2-modified groundnut shell: optimization, equilibrium, kinetic, and thermodynamic studies

Abstract

This study investigated the viability of using waste groundnut shells (GSs) to produce efficient biosorbent capable of removing nitrophenol from aqueous solution. Waste GSs were washed thoroughly, dried, reduced to 2 mm particle size, and activated with ZnCl 2 . The surface and physical properties (moisture and ash content) of the activated GSs (AGSB) were characterized using Fourier transform infrared spectrometer (FTIR), and standard methods. Biosorption of nitrophenol was optimized using Box-Behnken design (BBD). Analysis of the optimization processes was carried out using statistical tools embedded in the Design Expert software (10.0.1). Batch biosorption was conducted to generate data to determine suitable adsorption isotherm models, adsorption kinetics models, and adsorption thermodynamics. The FTIR spectra of AGSB indicate a major shift in the functional groups after the activation process. The moisture and ash content of AGSB were 9.0% and 3.1%, respectively. The optimum adsorption capacity (AC) and removal efficiency (RE) obtained at 20 mg/L, 80 min, and 1.6 g were 7.888 mg/g and 90.62%, respectively. The AC and RE were well suited to quadratic models with correlation coefficient (R 2 ) of 0.9853 and 0.9914, respectively. Langmuir isotherm and pseudo-second-order kinetic models with R 2 of 0.999 and 0.9843 were most suitable. The enthalpy, entropy, and Gibb's free energy were in the ranges m − 20.46 to − 4.36, 20.14 to 86.17, and − 21.49 to − 5.02 kJ/mol, respectively. This study demonstrated the effectiveness of AGSB as biosorbent for wastewater treatment, thus facilitating the conversion of solid wastes for the amendment of nitrophenol concentration in the wastewater stream.

Selection of Mass Transfer Models for Competitive Adsorption of Antibiotics Mixture from Aqueous Solution on Delonix regia Pod Activated Carbon

“…The values of ϴ less than unity show that intraparticle diffusion or pore diffusion is one of the rates determining steps. However, the linearity of the Bangham plot suggests that adsorbate pore diffusion is not the only rate-controlling step (Amole et al, 2021).…”

“…Antibiotic usage increased rapidly and concerns focused on their residues in the aquatic environment have become a global problem posing a serious threat to the environment and an inherent health risk to human beings (Azarpira et al 2019). Various treatment techniques employable for the r the removal of antibiotics from wastewater streams include, biodegradation, membrane filtration, ozonation, and, reverse osmosis (Amuda et al, 2015), however, their efficacies are challenged by economic and technical feasibilities (Amole et al, 2021). The choice of adsorption technique has been welcomed in many studies due relative higher efficiency in removing dissolved organics (Amole et al, 2021).…”

“…Various treatment techniques employable for the r the removal of antibiotics from wastewater streams include, biodegradation, membrane filtration, ozonation, and, reverse osmosis (Amuda et al, 2015), however, their efficacies are challenged by economic and technical feasibilities (Amole et al, 2021). The choice of adsorption technique has been welcomed in many studies due relative higher efficiency in removing dissolved organics (Amole et al, 2021). There is, therefore, a growing interest in novel and low-cost adsorbents.…”

“…Kinetics studies of the adsorption process are employed to decide and establish the adsorption rate mechanisms and the possible rate that controls the adsorption process (Revellame et al 2020). The general adsorption process used to determine the mechanism of adsorbate(s) onto selected adsorbent is assumed to occur using a three-step model, which is (i) mass transfer of adsorbate from the bulk solution to the adsorbent surface, (ii) adsorption of adsorbate onto sites and (iii) internal diffusion of adsorbate through either a pore diffusion model or a homogeneous solid-phase diffusion model (Amole et al, 2021). The basic principle behind the rate of adsorption mechanisms involves the search for the best model that best fits the data generated.…”

Use of Biochar Prepared from the Açaí Seed as Adsorbent for the Uptake of Catechol from Synthetic Effluents

“…However, these methods have limited applications and are complex and expensive. Conversely, adsorption is a suitable method for the treatment of organic compounds containing wastewater [ 14 , 15 , 16 ] because it is a simple, economical process, and it enables the use of the lignocellulosic materials in the pristine form [ 17 ] or as precursors for the preparation of adsorbents [ 18 , 19 , 20 ]. In addition, these adsorbents can be used to remove substances dissolved in water [ 19 , 20 ].…”