Raw Eggshell as an Adsorbent for Copper Ions Biosorption—Equilibrium, Kinetic, Thermodynamic and Process Optimization Studies

Mining industries frequently generates acid mine drainage (AMD) either by its operating or abandoned mines which are often characterized by an elevated levels of certain heavy metals, sulphate, low pH and some other toxic impurities in mine water creates environmental and ecological problems. Present study planned to suggest role of alga Spirogyra verrucosa in Manganese (Mn) removal by biosorption process from the mine water of Manganese mines of Nagpur District, Vidarbha Region, Maharashtra. The biosorption of Mn(II) ions from aqueous solution by using dead green algal (S.verrucosa) biomass was investigated by studying effect of pH, temperature, quantity of biosorbent, contact time as well as initial metal ion concentration. The optimized values obtained with respect to these parameters clearly indicates that pH 5, temperature 30°C, biosorbent quantity 1.0 gm/l, contact time 120 min. and initial metal ion concentration 50mg/l were the basic requirement for the biosorption of Mn(II) ions by dead algal biomass. Also, the biosorption kinetic and isotherm modeling applied to the equilibrium data for biosorption of Mn(II) ions onto alga reveals the fitness of the pseudo-second-order rate expression (R2=0.994) as well as the suitability of Langmuir (R2=0.859) and Freundlich (R2=0.761) isotherm models with an indication of the applicability of this metal ion-dried algal system for removal of Mn(II) ions in a monolayer biosorption as well as heterogenous surface conditions. However, comparatively biosorption equilibrium was better described by Langmuir isotherm model with monolayer biosorption capacity of S.verrucosa biomass 21.80 mg/g. Also, the maximum removal 40.66 mg/g (80.20%) of Mn(II) ion by alga under optimized conditions promises the potential use in mine water treatment technology.

In the present study, a calcium alginate bead adsorbent was prepared from brown algae (Macrosystis pyrifera) and was used for removal of Pb+2, Cu+2, and Sb+3 ions from aqueous solutions, using a fixed bed column. The initial concentration of metal ions, mass of adsorbent, recirculation flow, hydrodynamic cavitation, and contact time were examined, and the adsorption kinetics and isotherms were systematically studied. The Taguchi five-factor methodology was used for the development at three levels of experimentation. Experiment N° 24 (concentration, 10 mg/L; flow rate, 10 mL/s; adsorbent mass, 10 g; hydrodynamic cavitation with maximum air flow, and treatment time 240 min) resulted in the maximum removal of 92%, 78%, and 16% of lead, copper, and antimony ions, respectively. The average rate constants corresponding to pseudo-second-order kinetics for lead, copper, and antimony ions were 5.3 × 10−3, 1.4 × 10−3, and 7 × 10−5 g.mg−1min−1, respectively. In the adsorption process, they closely approximate to Langmuir and Freundlich isotherms, with adsorption capacities for Pb2+, Cu2+, and Sb3+ of 7.60, 2.07, and 0.37 mg/g, respectively, with good bioadsorption affinity of Pb > Cu > Sb. It was demonstrated that the bioadsorption equipment, with proper control of the factors, achieves concentration values of lead and copper ions below the current environmental regulations. The results of these studies indicated that calcium alginate is a promising adsorbent for separating and recovering heavy metal ions from contaminated water, although further research is needed for antimony ions.

Yttrium is an element of critical importance for industry and technology. Cyanobacteria Arthrospira platensis was employed for Y(III) recovery from contaminated wastewater through biosorption and bioaccumulation processes. The effect of pH of a solution, contact time, temperature, and initial Y(III) concentration on the adsorption behaviour of Arthrospira platensis were studied. The maximum adsorption capacity of 719.8 mg/g was attained at a pH of 3, temperature of 20 °C, and adsorption time of 3 min. The Langmuir and Freundlich isotherm models were suitable to describe the equilibrium of the biosorption, while kinetic of the process followed the pseudo-first-order model. Thermodynamic parameters showed that the biosorption process was spontaneous and exothermic in nature. In bioaccumulation experiments, Arthrospira platensis was able to remove up to 70% of Y(III) from the solution. Beside biomass uptake capacity, the toxic effect of Y(III) on the biomass productivity and biochemical composition was assessed. Thus, Y(III) in concentration of 10–30 mg/L led to a decrease in the content of proteins, carbohydrates, and phycobiliproteins in the biomass and had no significant negative impact on productivity and photosynthetic pigments content. Experiments performed using Arthrospira platensis showed that biological objects have a great potential to be applied for the recovery of rare earth elements from wastewater.

Citric acid modified mixed hardwoods powder (CMH) was prepared as a biosorbent to remove copper ions and methylene blue (MB) from aqueous solution by batch techniques. FT-IR and XRD were used to characterize the biosorbent. The effects of initial pH value, biosorption temperature, contact time, and initial adsorbate concentration on the biosorption capacities and adsorptivity of Cu2+ and MB onto CMH were investigated. The results showed that CMH exhibited excellent biosorption characteristics for Cu2+ and MB. The maximal biosorption capacity of Cu2+ and MB onto CMH was 165.0 and 237.4 mg/g at 20 °C, respectively. The biosorption kinetics studies indicated that Cu2+ and MB biosorption followed the pseudo-second-order model. The biosorption may be controlled by external intraparticle diffusion mass transfer during the whole biosorption process. Furthermore, the biosorption-equilibrium can be well described by Langmuir and Freundlich isotherm models.

Optimization of heavy metal removal from aqueous solutions by maghemite (γ-Fe2O3) nanoparticles using response surface methodology

The Cercis siliquastrum tree leaves are introduced as a low cost biosorbent for removal of Ag(I) from aqueous solution in a batch system. FT‐IR, XRD analysis, and potentiometric titration illustrate that the adsorption took place and the acidic functional group (carboxyl) of the sorbent was involved in the biosorption process. In addition, it was observed that the pH beyond pHpzc 4.4 is favorable for the removal procedure. The effect of operating variables such as initial pH, temperature, initial metal ion concentration, and sorbent mass on the Ag(I) biosorption was analyzed using response surface methodology (RSM). The proposed quadratic model resulting from the central composite design approach (CCD) fitted very well to the experimental data. The optimum condition obtained with RSM was an initial concentration of Ag(I) of 85 mg L−1, pH = 6.3 and sorbent mass 0.19 g. The applicability of different kinetic and isotherm models for current biosorption process was evaluated. The isotherm, kinetic, and thermodynamic studies showed the details of sorbate‐sorbent behavior. The competitive effect of alkaline and alkaline earth metal ions during the loading of Ag(I) was also considered.

BackgroundCadmium pollution from industrial effluent can cause major health concerns, so it must be removed from wastewater prior to disposal. The objective of this study was to remove cadmium (Cd2+) from aquatic environments using red macroalgae Digenia simplex pretreated with calcium chloride (CaCl2) (DSC).MethodsBatch adsorption studies were carried out to evaluate the individual impacts of adsorbent-metal contact time, cadmium concentration, and temperature on the cadmium removal efficiency and biosorption capacity. The Box-Benhken experimental design of response surface methodology was also used to investigate the relationship between different factors (pH, Cd2+ concentration and algal dose) and the cadmium removal efficiency of pretreated D. simplex.ResultsThe highest removal efficiency of 97.27% was achieved by combining different optimal parameters, including pH 5.78, initial Cd2+ concentration of 24.79 mg/L, and adsorbent dosage of 6.13 g/L. Moreover, cadmium removal from agricultural wastewater samples by pretreated D. simplex was evaluated under the optimal conditions, and the removal rate excessed 97%. Kinetic and isotherm investigations showed that the pseudo-second-order, Freundlich, Langmuir, and Dubinin–Radushkevich models of cadmium biosorption on pretreated algal biomass correlated well with the experimental biosorption data, implying that the biosorption of Cd2+ is a homogeneous monolayer and multilayer chemisorption process. The equilibrium isotherm data indicated that the biosorption capacity of the biosorbent was 11.16 mg/g as determined by the Langmuir model. Furthermore, the biosorption process was evaluated as an endothermic process with entropy and enthalpy values of 0.134 kJ/mol K and 38.01 kJ/mol, respectively. The functional groups, surface morphology, and elemental composition of the algal biomass were investigated, revealing the porous nature of the cell surface and the abundance of functional groups responsible for the Cd2+ biosorption process. These results suggest that DSC biomass can be used as a biosorbent for the effective removal of Cd2+ ions from effluent due to its availability and strong biosorption capability.

ABSTRACTIn this study, the capacity of a natural macroalgae consortium consisting of Chaetomorpha sp., Polysiphonia sp., Ulva sp. and Cystoseira sp. species for the removal of copper ions from aqueous environment was investigated at different operating conditions, such as solution pH, copper ion concentration and contact time. These environmental parameters affecting the biosorption process were optimized on the basis of batch experiments. The experimentally obtained data for the biosorption of copper ions onto the macroalgae-based biosorbent were modeled using the isotherm models of Freundlich, Langmuir, Sips and Dubinin–Radushkevich and the kinetic models of pseudo-first-order, pseudo-second-order, Elovich and Weber and Morris. The pseudo-first-order and Sips equations were the most suitable models to describe the copper biosorption from aqueous solution. The thermodynamic data revealed the feasibility, spontaneity and physical nature of biosorption process. Based on the data of Sips isotherm model, the biosorption capacity of biosorbent for copper ions was calculated as 105.370 mg g−1 under the optimum operating conditions. A single-stage batch biosorption system was developed to predict the real-scale-based copper removal performance of biosorbent. The results of this investigation showed the potential utility of macroalgae consortium for the biosorption of copper ions from aqueous medium.

To remove heavy metals from aqueous solution and reclaim valuable materials from mushroom byproducts, Flammulina velutipes spent substrate (FVSS) was developed as a novel biosorbent for copper ion removal. Batch experiments demonstrated that ion removal was pH-, biosorbent dosage- and initial metal concentration dependent. The maximum removal capacity of 15.56 mg/g was achieved at pH 6.0 with a biomass dosage of 3.0 g/L and initial copper ion concentration of 50 mg/L. The adsorption data were in compliance with the Langmuir isotherm and a pseudo-second-order kinetic model. Thermodynamic studies revealed the biosorption process was endothermic, random, and spontaneous. FT-IR spectral analysis confirmed that hydroxyl, amino, carbonyl, and phosphate groups on the biosorbent surface were involved in the biosorption. The uneven surface and porous structure of the biosorbent was propitious for quickly capturing the metal ions from aqueous solution. EDX spectra revealed that the copper ions were loaded on the surface of the biosorbent. XRD patterns showed the formation of copper-containing compounds.

Biosorption is an effective means of removal of heavy metals from wastewater. In this work the biosorption behavior of Cladophora fascicularis was investigated as a function of pH, amount of biosorbent, initial Cu2+ concentration, temperature, and co-existing ions. Adsorption equilibria were well described by Langmuir isotherm models. The enthalpy change for the biosorption process was found to be 6.86 kJ mol(-1) by use of the Langmuir constant b. The biosorption process was found to be rapid in the first 30 min. The presence of co-existing cations such as Na+, K+, Mg2+, and Ca2+ and anions such as chloride, nitrate, sulfate, and acetate did not significantly affect uptake of Cu2+ whereas EDTA substantially affected adsorption of the metal. When experiments were performed with different desorbents the results indicated that EDTA was an efficient desorbent for the recovery of Cu2+ from biomass. IR spectral analysis suggested amido or hydroxy, C=O, and C-O could combine strongly with Cu2+.

Contamination of wastewater by toxic metals is a global environmental concern. In this study, the possibility of using inactive (dead) Sargassum baccularia powder as a natural adsorbent was investigated in the removal of cadmium from aqueous solutions. The biosorption process was found to be highly dependent on a set of variables such as pH, temperature, contact time, shaking speed and initial metal concentration. The results showed an optimum pH value, (6.0) for cadmium, where was the biosorption capacity (842.15±0.252) for cadmium, and the lowest biosorption value for Cd was found at pH 2.0. The optimum temperature in this study was 30 °C. The time required for equilibrium was investigated over a period of 360 min and found to be 180 min. The capacity of biosorption increased with increasing shaking speed, and the highest uptake value was found at 120 rpm. The maximum removal of Cd +2 was found at 20 mg/l. The models Freundlich and Langmuir were used to study the equilibrium process of these systems. The Langmuir model was found to be more suitable for the interpretation of these systems by the value of the correlation coefficients higher than 0.99. Brown seaweed powder is an effective, low-cost, and environmentally friendly adsorbent for removing metals from aqueous solutions, according to the results obtained

Equilibrium, thermodynamic, and kinetic studies on the biosorption of Cu(II) using biomass, Trichoderma viride were carried out. The biosorbent was characterized by Fourier transform infrared spectroscopy and Scanning Electron Microscopy. The Langmuir and Freundlich isotherm models were applied to describe the biosorption process. The influence of pH, the biomass dosage, the contact time, the initial metal ion concentration, and the temperature of the solution on the biosorption was studied. The maximum Cu(II) biosorption was attained at pH 5. The equilibrium data were better fit by the Langmuir isotherm model than by the Freundlich isotherm. The maximum biosorption capacity of T. viride biomass was found to be 19.6 mg/g for Cu(II). The kinetic studies indicated that the biosorption of Cu(II) followed the pseudo-second-order model. The calculated thermodynamic parameters, Gibbs-free energy (ΔGo), enthalpy (ΔHo), and entropy (ΔSo) showed that the biosorption of Cu(II) onto T. viride biomass was spontaneous and endothermic. It can be concluded that the T. viride biomass has the potential as an effective and low-cost biosorbent for Cu(II) removal from aqueous solutions.

Equilibrium modeling for adsorptive removal of Indosol Black NF dye by low-cost agro-industrial waste: batch and continuous study

This study has been focused on the batch culture removal of Cu2+ and Ni2+ ions from the aqueous solution using marine brown algae Sargassum angustifolium. Influences of parameters like pH, initial metal ions concentration and biosorbent dosage on nickel and copper adsorption were also examined using the Box–Behnken design matrix. For biosorption of Cu2+ the optimum pH value was determined as 5.0, optimum biosorbent concentration to 1.0 g/L and optimum initial concentration 0.15 mmol/L. For the biosorption of Ni2+, the optimal condition was the same but the optimum pH value was determined as 6.0. Desorption experiments indicated that CH3COOH and EDTA were efficient desorbents for recovery from Cu2+ and Ni2+. The Langmuir isotherm model was applied to describe the biosorption of the Cu2+ and Ni2+ into S. angustifolium. The maximum uptake of Cu2+ and Ni2+ ions by the S. angustifolium biomass under the optimal conditions was approximately 0.94 and 0.78 mmol/g dry alga, respectively. Response surface models showed that the data were adequately fitted to a second-order polynomial model. Analysis of variance showed a high coefficient of determination value (R2=0.993 for Cu2+ and 0.991 for Ni2+) and a satisfactory second-order regression model was derived. In addition, results reported in this research demonstrated the feasibility of employing S. angustifolium as biosorbent for Ni2+ and Cu2+ removal.

Improved adsorption performance of nanostructured composite by ultrasonic wave: Optimization through response surface methodology, isotherm and kinetic studies