Industries generating wastewater with elevated concentrations of pollutants (e.g. metals, dyes, phenolic compounds, anions, etc.) need specialized atreatment systems. Adsorption is one of the most extensively applied techniques for the removal of pollutants from the industrial effluents. The prominent and emerging trend of subjecting biosorbent in the adsorption technology is mainly because of their natural existence, abundance, renewable, biodegradable and economic features. The adsorption isotherm equations used to describe the experimental data and the thermodynamic assumptions of the models often provide some insight into the sorption mechanism, the surface properties and affinity of the biosorbent. This paper presents a state of the art on the review of adsorption isotherm models in an exhaustive manner on the basis of two, three, four and five parameters respectively. Focuses on the various sources of agricultural byproducts as biosorbents and describes on the potential applications of different adsorption isotherm models for the evaluation of the wastewater pollutants biosorption. It is evident from the literature survey that various adsorption isotherm models have been considered under study by the researchers but mostly two and three parameter isotherm model were best fitted the equilibrium data. This paper reviews the adsorption isotherm models on the basis of parameters that can be applied for exploring a novel biosorbents.

Relevance of isotherm models in biosorption of pollutants by agricultural byproducts

Synthesis of magnetic γ-Fe2O3-based nanomaterial for ultrasonic assisted dyes adsorption: Modeling and optimization.

Thallium pollution in China and removal technologies for waters: A review.

Screening and optimization of highly effective ultrasound-assisted simultaneous adsorption of cationic dyes onto Mn-doped Fe3O4-nanoparticle-loaded activated carbon.

A comprehensive review on magnetic carbon nanotubes and carbon nanotube-based buckypaper for removal of heavy metals and dyes

Simultaneous removal of binary mixture of Brilliant Green and Crystal Violet using derivative spectrophotometric determination, multivariate optimization and adsorption characterization of dyes on surfactant modified nano-γ-alumina.

Taguchi L16 orthogonal array optimization for Cd (II) removal using Carpinus betulus tree leaves: Adsorption characterization

Sugar beet pulp, a waste-product of sugar-refining factories, is suggested as sorbent to remove thallium(I) from aqueous solutions in a batch process. The sorbent is enhanced in its removal efficiency by pretreatment with NaOH. The effects of pH, temperature, sorbent dosage, and initial concentration of Tl(I) are considered. The sorption process has been found to be rapid. Maximum removal efficiency of Tl(I) is observed at values of pH from 5 to 9 with a sorbent amount of 7 g L−1. Various isotherm models such as Langmuir, Freundlich, and Dubinin–Redushkevich isotherms are considered to describe the sorption process. The equilibrium data fit well to the Langmuir model with a maximum uptake capacity of 185 mg g−1. The thermodynamic parameters ΔG, ΔH, and ΔS indicate that the process is spontaneous and exothermic.

Removal of thallium(I) from aqueous solution using modified sugar beet pulp

In this study a simple method was developed to fabricate a glassy carbon electrode (GCE) modified by a composition of multi-wall carbon nanotubes (MWCNTs) and nano nickel hydroxide (NNH). The NNH powder was synthesized by coordination homogeneous precipitation (CHP) method and characterized by means of SEM and XRD techniques. Applicability and suitability of NNH–MWCNTs/GC electrode for determination of 4-chlorophenol (4-CP) were subsequently checked in details using different methods such as cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and chronocoulometry (CC). The DPV data showed that NNH–MWCNTs/GCE enhances significantly the oxidation peak current of 4-CP in compare with bare GCE and MWCNTs/GCE, which it indicates that Ni(OH)2 possesses an active surface area toward 4-CP oxidation. Response surface methodology (RSM) was used to optimize voltammetric response of modified electrode for determination of 4-CP. Initial solution pH, nickel hydroxide amount in modifier matrix and dropping volume of this mixture were considered as three important operating factors through experimental design methodology. The central composite design (CCD) as a response surface approach was applied for obtaining the optimum conditions as well as the maximum height of 4-CP oxidation peak. Under the optimal experimental conditions, the current oxidation peak was proportional to the 4-CP concentration in a range of 1.0–750 μM with a detection limit (S/N = 3.0) of 0.5 μmol L−1. Using the proposed method, 4-CP was successfully determined in water samples with standard addition method, suggesting that this method can be applied to determine 4-CP in water samples.

Multivariate optimization of a new 4-chlorophenol sensor fabricated by modification of glassy carbon electrode using Ni(OH)2 nanoparticles-carbon nanotubes (NNH–MWCNTs)

Catalpa speciosa tree leaves were used to remove Pb(II) from aqueous solutions. Removal process was optimized by applying experimental design strategy. Optimization was based on the application of a two-level full-factorial design for screening the significant variables followed by a Doehlert design to find out an appropriate model which leads to determine the optimum conditions. The empirical models were developed in terms of effective factors: pH, initial concentration of metal ion Cm and sorbent mass(s) have been found statistically adequate to describe the process responses, that is, removal percent and the capacity uptake of Pb(II). The multiresponse optimization of Pb(II) removal process has been carried out using desirability function approach. To this end, Derringer’s desirability function (D) has been applied for mathematical optimization of the simultaneous multiresponse problem. Thus, the optimum conditions of Pb(II) removal process have been found as: pH = 4.43, s = 0.07 g, and Cm = 10...

Tahere Shariatmanesh

Papers

Simultaneous removal of binary mixture of Brilliant Green and Crystal Violet using derivative spectrophotometric determination, multivariate optimization and adsorption characterization of dyes on surfactant modified nano-γ-alumina.

Taguchi L16 orthogonal array optimization for Cd (II) removal using Carpinus betulus tree leaves: Adsorption characterization

Removal of thallium(I) from aqueous solution using modified sugar beet pulp

Multivariate optimization of a new 4-chlorophenol sensor fabricated by modification of glassy carbon electrode using Ni(OH)2 nanoparticles-carbon nanotubes (NNH–MWCNTs)

Doehlert design as optimization approach for the removal of Pb(II) from aqueous solution by Catalpa Speciosa tree leaves: adsorption characterization