A natural macroalgae consortium for biosorption of copper from aqueous solution: Optimization, modeling and design studies

Biosorption of Ni(II) from electroplating wastewater by modified (Eriobotrya japonica) loquat bark

The study on the biosorption of copper ions using raw eggshells as an adsorbent is presented in this paper. The influence of different process parameters, such as: initial pH value of the solution, initial Cu2+ ions concentration, initial mass of the adsorbent, and stirring rate, on the biosorption capacity was evaluated. The SEM-EDS analysis was performed before and after the biosorption process. SEM micrographs indicate a change in the morphology of the sample after the biosorption process. The obtained EDS spectra indicated that K, Ca, and Mg were possibly exchanged with Cu2+ ions during the biosorption process. The equilibrium analysis showed that the Langmuir isotherm model best describes the experimental data. Four kinetic models were used to analyze the experimental data, and the results revealed that the pseudo-first order kinetic model is the best fit for the analyzed data. Calculated thermodynamic data indicated that the biosorption process is spontaneous, and that copper ions are possibly bound to the surface of the eggshells by chemisorption. The biosorption process was optimized using Response Surface Methodology (RSM) based on the Box-Behnken Design (BBD), with the selected factors: adsorbent mass, initial metal ion concentration, and contact time.

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.

It is crucial to identify more biological adsorbents that can efficiently uptake metals from wastewater. Dry haloalkaliphilic archaea Natronolimnobius innermongolicuswas evaluated for Cd ions biosorption. The optimal operating conditions (pH, biomass dose, initial metal concentration, contact time, and isotherms models) were tested. Biosorption process is influenced by the metal's solution pH with maximum removal of 83.36% being achieved at pH 8. Cadmium ions uptake reaches equilibrium in about 5 min of biosorption process. The Langmuir model was determined to better fit the Cd(II) biosorption by dry archaea. The maximal uptake capacity (qmax) of Cd(II) was 128.21 mg/g. The effect of multi-component system on biosorption behaviour of Pb, Ni, Cu, Fe, and Cd ions by immobilized dried archaeal cells, dried archaeal cells, and dried bryozoa was studied using Plackett–Burman experimental design. The investigated biosorbents were effective at removing metals from contaminated systems, particularly for Fe, Pb, and Cd ions. Moreover, the interaction behaviour of these metals was antagonistic, synergistic, or non-interactive in multi-metals system. SEM, EDX, and FTIR spectra revealed changes in surface morphology of the biomass through the biosorption process. Finally, continuous adsorption experiment was done to examine the ability of immobilized biomass to adsorb metals from wastewater.

Magnesium-aluminium hydrogenphosphate layered double hydroxide that synthesized by used of co-precipitation and followed by hydrothermal (MAHP4) method was used as an adsorbent to remove copper ions from aqueous solutions. The effects of various optimization parameters such as contact time, adsorbent dosage and lead ion concentrations were investigated by used of Response surface methodology (RSM). The Response surface methodology (RSM) based on a four-level-three variables Central Composite Rotatable Design (CCRD) was employed to evaluate the interactive effects of the various optimization parameters. The parameters were contact time (2-6 h), adsorbent dosage (0.01 0.05 g) and copper ion concentrations (50 100 mg/l). Simultaneously by increasing contact time and amount of dosage of MAHP4 used, the percentage of lead ion removal from aqueous solution was increased. However, the percentage removal decreases with an increase in concentrations of copper ion. The experimental percentage removal recorded under optimum conditions was compared well with the maximum predicted value from the RSM which suggest that fractional factorial design of RSM can be used to study the removal of copper from aqueous solution by used of magnesium-aluminium hydrogenphosphate layered double hydroxide as an adsorbent.

Graphene oxide has drawn attention globally as it emerged as a promising adsorbent material with enhanced adsorption of environmental pollutants due to its eco-friendly attributes, high surface area, and cost-effectiveness for mass production. This economical solution is a promising and potentially transformative approach to heavy metal removal, contributing to a cleaner and more sustainable future. In this study, unmodified and modified graphene oxide were examined for the removal of copper (II) ions in an aqueous solution. Modified Hummer’s method was utilized to synthesize the graphene oxide. The synthesized graphene oxide was then modified with N- trimethoxysilylpropylethylenediaminetriaceticacid (EDTA-silane), resulting in EDTA-modified graphene oxide (EGO). Batch adsorption tests were done for both adsorbents in order to determine the effects of various factors, such as pH, adsorbent dosage, and contact time. Additionally, in order to describe the adsorption behavior of the adsorption system, it was further fitted to isotherm and kinetic adsorption models. Results of adsorption study showed optimum adsorption for copper (II) ions was achieved at pH = 7, contact time = 45 min, and adsorbent dosage of 5 mg and 4 mg of unmodified graphene oxide (GO) and modified graphene oxide (EGO), respectively. The fundamental mechanism of both adsorbents was best explained by Langmuir isotherm model and the pseudo-second-order model, indicating that the adsorption system followed chemisorption. The adsorption capacity and maximum removal of copper (II) ions was 672.22 mg/g and 78.41% for GO, and 729.11 mg/g and 89.94% for EGO. The latter suggested that graphene oxide treated with EDTA-silane (EGO) has the higher capacity to adsorb copper (II) ions.

In the presented study, a new and efficient sorbent for the removal of Everzol Red 3BS dye from aqueous solutions was prepared by immobilization of 2,4-­dinitrophenyl hydrazine (DNPH) on γ-alumina (γ-Al2O3) ­nanoparticles coated with sodium dodecyl sulfate (DNPH­­­-­γ-alumina). The structure and morphology of the produced sorbents were characterized by Fourier Transform Infrared (FT-IR) and Scanning electron microscopy (SEM). Batch studies were performed to study the effect of various experimental parameters such as contact time, initial dye concentration, adsorbent dose and solution pH on the adsorption process. The experimental data were analyzed using the Langmuir and Freundlich isotherm models. The isotherm studies showed that the adsorption experimental data were fitted by Langmuir isotherm model. The maximum monolayer adsorption capacity (qmax) ­obtained from the Langmuir model was 10.21 and 86.96 mg/g for Everzol Red 3BS dye on nano-γ-alumina and DNPH modified γ-alumina nanoparticles (DNPH­­­-­γ-alumina), respectively. Meanwhile, thermodynamic parameters such as Gibbs free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) were evaluated. We found out that ∆G°, ∆H°, and ∆S° for nano-γ-alumina and DNPH modified γ-alumina nanoparticles (DNPH­­­-­γ-alumina) are -11.07 and -4.84 kJ/mol, 1.40and 3.55 kJ/mol, and 0.037 and 0.025 kJ/molK, respectively. The negative values of Gibbs free energy change (∆G°) ­show that the adsorption was feasible as the spontaneous and positive values of enthalpy change (∆H°) confirm the endothermic adsorption­­. The obtained results indicate that γ-alumina (γ-Al2O3) ­nanoparticles modified with 2, 4-dinitrophenyl hydrazine (DNPH- γ-alumina) can be used as an efficient adsorbent material for the adsorption of anionic dyes from aqueous solutions.

Pesticide contamination has led to serious environmental issues that pose a significant threat to living organisms throughout the world. Therefore, the significant removal of pesticides from aquatic environments has attracted the attention of environmental scientists and academicians in recent decades. Hence, in the present investigation, the iron nanoparticles (INPs) from tea waste were fabricated as an efficient adsorbent towards the removal of profenofos (PF) from aqueous solution. The as-synthesised INPs were systematically characterised by various analytical techniques such as Ultra Violet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (PXRD) and dynamic light scattering (DLS). Various influencing factors such as contact time, adsorbent dosage, solution pH and initial concentration of pesticide were systematically optimised for the maximum adsorption efficiency of PF by the prepared INPs. Based on the obtained results, the INPs showed greater adsorption efficiency towards the removal of PF. The kinetic data were analysed using various adsorption kinetic models such as pseudo-first-order, pseudo-second-order and intra-particle diffusion. Further, the interaction between prepared INPs and PF was evaluated using various adsorption isotherm models such as Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) models. The monolayer Langmuir adsorption capacity of 43.67 mg g−1 was obtained with a minimum contact time of 15 min. According to the kinetic and isotherm data, the pseudo-second-order kinetic and Langmuir isotherm models were found to be well fitted for PF adsorption using the prepared INPs. The obtained findings of this study clearly demonstrated that the fabricated INPs are an efficient material towards the removal of pesticide molecules from aquatic environments.

Adsorption characteristics of Cu(II) and Pb(II) onto expanded perlite from aqueous solution

The adsorption characteristics of Copper (II) ions on Iraqi attaplugite and flint clays from synthetic solutions have been studied with relate to variations in contact time, solution pH, solution temperature, and adsorbents dose. All experiments were carried out via batch manner. The maximum removal efficiency of copper (II)ions onto attaplugite was 99.945% at (PH ≈ 5, adsorbent dosage was 0.5 g, contact time was 40 minute, initial concentration was 100 mg/L, and temperature 298K), while the maximum removal efficiency of copper (II)ions onto flint clay was 64.322% at (PH≈5,adsorbent dosage0.3 g, contact time 10 minute, initial concentration 100 mg/L and temperature 298K). The copper (II) adsorption on attaplugite clay was fit with Freundlich and Langmuir isotherms, while the copper (II) adsorption on flint clay was fit with Freundlich and D-R isotherms. The copper ions adsorption kinetic onto attapulgite and flint clays were agree with pseudo second order. The thermodynamic values of ΔG° for copper ions adsorption were negative in those processes, suggesting a spontaneously system. The ΔS° values for copper ions adsorption onto attaplugite clay were positive, suggesting an increase of randomness, while the ΔS° values for copper ions adsorption onto flint clay were negative, suggesting an increase of order. The values of ΔH° for copper ions adsorption onto attaplugite clay were positive, suggesting an endothermic process, while the values of ΔH° for copper ions adsorption on flint clay were negative, suggesting an exothermic process. The values of ΔG° and main adsorption energy (E) in this work suggest that copper ions adsorption on attapulgite and flint clays was classified as physisorption. After adjust all the optimum conditions from batch experiments onto synthetic water, we applied the optimum conditions onto the Al-Quds Power Station wastewater sample. The maximum removal efficiency of copper (II) ions onto attaplugite clays was 99.67% (Conc. of copper ions decrease from 97.39 to 0.321mg/L) at (PH≈5,adsorbent amount 0.5g,equilibrium time 40 minute, and temp. 328K), while maximum removal efficiency of copper (II)ions onto flint clay was 39.83% (Conc. of copper ions decrease from 97.39 to 58.59 mg/L) at (PH.≈.5,adsorbent amount 0.3g,contact time 10 minute, and temperature 298K).

Naturally-based poly(acrylic acid) grafted sodium alginate di-block hydrogels were investigated as high efficiency biosorbents for copper(II) ion. The grafted di-block hydrogel was characterized using FTIR, TGA and SEM techniques. Blank and immobilized algal biosorbent beads formed via 2.0% (w/w) calcium ions were also investigated. Batch adsorption experiments revealed optimal pH dependence of copper(II) ion biosorption at pH 5.5 with high efficient copper(II) ion uptake of 98.5 mg/g. The dynamics studies showed that the high efficiency copper(II) ion biosorption followed pseudo-second order kinetics with significant contribution of intraparticle diffusion mechanism. The equilibrium data fitted to Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) adsorption isotherm models. Thermodynamics parameters for copper(II) biosorption on blank and immobilized algal beads depicted the spontaneous nature of the biosorption process. Such high efficiency, feasibility, simplicity, and low cost properties adapt the di-block biosorbent to be the next generation promising biosorbents for water decontamination and to help in the recovery of the missing ecologic harmony.

The aim of this study is to evaluate adsorption kinetics, isotherms and thermodynamic parameters of crystal violet (CV) and methylene blue (MB) dyes from aqueous solution using waste foundry sand. Adsorption studies were carried out at different initial dye concentrations (12.5-400 mg l−1), contact time (5-240 min), pH (3.0-9.0), sorbent doses (0.125-2 g l−1) and adsorption temperature (20°C-70°C). The equilibrium adsorption data were analysed by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DRK) adsorption isotherm models. Of the four adsorption isotherms, the R2 value of Langmuir isotherm model for MB and CV were 0.969 and 0.926, respectively. Experimental data were analysed using the pseudo-first order, the pseudo-second order, intraparticle diffusion and Elovich models. The characteristic parameters for each model have been determined. In addition, the equilibrium thermodynamic parameters, including changes in Gibbs free energy, entropy and enthalpy are determined for the CV and MB on waste foundry sand.

Biosorption of cesium(I) from aqueous solution by a novel exopolymers secreted from Pseudomonas fluorescens C-2: Equilibrium and kinetic studies

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.

The biosorption characteristics of lanthanum and cerium ions from aqueous solution by grapefruit peel have been investigated as a function of pH, biosorbent dosage, contact time, and temperature. The pH was found to be significantly affecting the biosorption performance: pH 5.0 was found to be an optimum pH for favorable biosorption of lanthanum and cerium ions. The experimental isotherm data were analyzed using Langmuir and Freundlich equations. The Langmuir model fits the equilibrium data better than the Freundlich model. According to the Langmuir equation, the maximum uptake for La(III) and Ce(III) ions were 171.20 and 159.30 mg/g, respectively. Pseudo-first-order and pseudo-second-order models were used to represent the kinetics of the process. The results show that the pseudo-second-order model is the one that best describes the kinetics of the biosorption of both metal ions. The calculated thermodynamic parameters (ΔG°, ΔH°, and ΔS°) show that the biosorption process is feasible, spontaneous, and endothermic at 20–50 °C. FTIR analysis demonstrates that carboxyl and hydroxyl groups are involved in the biosorption of the metal ions. This study shows that grapefruit peel has the potential of application as an efficient biosorbent for the removal of lanthanide elements from aqueous solutions.