Biosorbent Dosage Research Articles

A Comparative Study of Cr(VI) Sorption by Aureobasidium pullulans AKW Biomass and Its Extracellular Melanin: Complementary Modeling with Equilibrium Isotherms, Kinetic Studies, and Decision Tree Modeling.

Melanin as a natural polymer is found in all living organisms, and plays an important role in protecting the body from harmful UV rays from the sun. The efficiency of fungal biomass (Aureobasidium pullulans) and its extracellular melanin as Cr(VI) biosorbents was comparatively considered. The efficiency of Cr(VI) biosorption by the two sorbents used was augmented up to 240 min. The maximum sorption capacities were 485.747 (fungus biomass) and 595.974 (melanin) mg/g. The practical data were merely fitted to both Langmuir and Freundlich isotherms. The kinetics of the biosorption process obeyed the pseudo-first-order. Melanin was superior in Cr(VI) sorption than fungal biomass. Furthermore, four independent variables (contact time, initial concentration of Cr(VI), biosorbent dosage, and pH,) were modeled by the two decision trees (DTs). Conversely, to equilibrium isotherms and kinetic studies, DT of fungal biomass had lower errors compared to DT of melanin. Lately, the DTs improved the efficacy of the Cr(VI) removal process, thus introducing complementary and alternative solutions to equilibrium isotherms and kinetic studies. The Cr(VI) biosorption onto the biosorbents was confirmed and elucidated through FTIR, SEM, and EDX investigations. Conclusively, this is the first report study attaining the biosorption of Cr(VI) by biomass of A. pullulans and its extracellular melanin among equilibrium isotherms, kinetic study, and algorithmic decision tree modeling.

Isotherm and Kinetic Adsorption of Cadmium (Cd) onto Biosorbent Made from Kepok Banana Peel (Musa Acuminata balbisian): the Effect of Activator Type and Biosorbent Dosage

The present study determined the isotherm and kinetics model of the cadmium adsorption process onto a biosorbent made from kepok banana peel (Musa Acuminata balbisian). The experiments were carried out in batch process, laboratories scale, room temperature, pH of Cadmium of 4, volume of Cd solution of 20 ml, and biosorbent size particle of 60 mesh—the biosorbent produced using chemical activation method onto dry banana peel. The variation in this research was the type of activator (H3PO4 and H2SO4) and the biosorbent dosage (1, 1.5, and 2 g). The experimental data was used to calculate the Langmuir and Freundlich isotherm—Kinetics analysis based on pseudo-first-order and second-order kinetics models. The best condition of the cadmium removal occurred at 90 minutes of contact time and 2 g dosage for H2SO4 and H3PO4 activators. Cadmium biosorption was in accordance with the Langmuir isotherm and pseudo-second-order kinetic model. The linear equation obtained is positive, with the maximum adsorption capacity and the affinity constant. Cadmium adsorption onto banana peel biosorbents followed the Langmuir adsorption isotherm pattern, so chemical adsorption occurred in this study. Cadmium adsorption kinetics onto biosorbent that activated with an acid activator of H3PO4 and H2SO4 followed the pseudo-second-order kinetic model. The best condition of the cadmium removal occurred at 90 minutes of contact time and 2 g dosage for H2SO4 and H3PO4 activators. Cadmium biosorption in this study was in accordance with the Langmuir isotherm and pseudo-second-order

Biosorption of Pb(II) Using Natural and Treated Ardisia compressa K. Leaves: Simulation Framework Extended through the Application of Artificial Neural Network and Genetic Algorithm.

This study explored the effects of solution pH, biosorbent dose, contact time, and temperature on the Pb(II) biosorption process of natural and chemically treated leaves of A. compressa K. (Raw-AC and AC-OH, respectively). The results show that the surface characteristics of Raw-AC changed following alkali treatment. FT-IR analysis showed the presence of various functional groups on the surface of the biosorbent, which were binding sites for the Pb(II) biosorption. The nonlinear pseudo-second-order kinetic model was found to be the best fitted to the experimental kinetic data. Adsorption equilibrium data at pH = 2-6, biosorbents dose from 5 to 20 mg/L, and temperature from 300.15 to 333.15 K were adjusted to the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models. The results show that the adsorption capacity was enhanced with the increase in the solution pH and diminished with the increase in the temperature and biosorbent dose. It was also found that AC-OH is more effective than Raw-AC in removing Pb(II) from aqueous solutions. This was also confirmed using artificial neural networks and genetic algorithms, where it was demonstrated that the improvement was around 57.7%. The nonlinear Langmuir isotherm model was the best fitted, and the maximum adsorption capacities of Raw-AC and AC-OH were 96 mg/g and 170 mg/g, respectively. The removal efficiency of Pb(II) was maintained approximately after three adsorption and desorption cycles using 0.5 M HCl as an eluent. This research delved into the impact of solution pH, biosorbent characteristics, and operational parameters on Pb(II) biosorption, offering valuable insights for engineering education by illustrating the practical application of fundamental chemical and kinetic principles to enhance the design and optimization of sustainable water treatment systems.

Potential Use of Agricultural Waste—Carob Kibbles (Ceratonia siliqua L.) as a Biosorbent for Removing Boron from Wastewater

The release of boron (B) into the environment as a result of anthropogenic activity modifies sustainable natural conditions, thus affecting ecosystems. To meet water quality regulations, commercial and natural boron adsorbents are available to reduce its concentrations in industrial effluents, with the former being not only more expensive but also less sustainable. In the publication, the biosorption parameters of carob kibbles (Ceratonia siliqua L.) were optimized in order to remove boron from aqueous solutions using batch experiments. The biosorbent used in the present research was agro-waste biomass provided by the local locust-beam gum industry. Boron removal by carob kibbles was favored at high initial pH values, and this capacity was found to be a function of boron initial concentration, biosorbent content in the solution, and particle size. The change in temperature did not affect the potential of biomass to remove boron. The highest boron removal efficiency (55.1%) was achieved under the following optimal conditions: 50 g/L biosorbent dose (Cs), with particle size range 0.025–0.106 mm, for the initial concentration (C0) of boron in the solution of 100 mg/L, at an initial pH of 11.5, for 5 h at 25 °C. This investigation suggests that carob kibble agro-waste can be valorized as a biosorbent to remove boron from wastewater, and the boron-loaded residue may eventually be explored as a new boron-fertilizer.

Kinetics and Thermodynamics of Sorption of Methylene Blue Dye Onto Raw Groundnut Shell Biosorbent

Dyes are one of the hazardous chemicals found in wastewater produced by textile and allied industries that need to be removed from the wastewater before it is released into water bodies. The sorption efficiency of raw groundnut shell (RGS), an agricultural waste, was tested on methylene blue (MB) dye through a batch adsorption experiment. Physicochemical analysis of the RGS indicated good biosorbent properties. Fourier transform infrared (FTIR) spectroscopy analysis of the RGS revealed the presence of heterofunctional groups. The effect of various biosorption parameters such as initial dye concentration, contact time, and biosorbent dosage was systematically investigated. The quantity of MB adsorbed increased as the initial concentration and contact time increased and decreased with an increase in biosorbent dose. A maximum uptake capacity of 29.3 mg/g was recorded for 50 mg/L MB initial concentration. The equilibrium data from the batch adsorption experiments were fitted well into Freundlich isotherm and pseudo-second-order kinetic models. The results from this study indicate that RGS can serve as an alternative, low-cost, eco-friendly and efficient adsorbent for the removal of MB dye from wastewater.

Biosorption Potential of Desmodesmus sp. for the Sequestration of Cadmium and Lead from Contaminated Water

Industrialization, urbanization, and natural processes have potentially accelerated the pace and level of heavy metals in the aquatic environment. Recently, modern strategies for heavy metal treatment in wastewater have received the specific attention of the scientific community. The present study aimed to assess the amorphous biomass of Desmodesmus sp. as a low-cost adsorbent to remove the cadmium (Cd) and lead (Pb) from aqueous solutions. It involved the optimization of pH, contact time, initial concentration of metal ions, and the dosage of biosorbent. Data collation revealed that an optimum contact time for both metals was 60 min, with an adsorption capacity of 63% for Cd and 66% for Pb. Different models were applied to the equilibrium data. The pseudo 2nd order described the best adsorption of Cd and Pb. The equilibrium data were computed with various isotherms. Langmuir isotherms better suit the adsorption of the above-mentioned metals. Hence, the maximum adsorption capacity of Desmodesmus sp. for Cd and Pb was 64.1 and 62.5 mg/g, respectively. The mechanism of biosorption was validated through a comparative FT-IR and Scanning Electron Microscopy of raw and metal-loaded algal biomass based on cell morphological changes. In order to study the reusability of adsorbent, adsorption-desorption of Cd and Pb ions was repeated three times using HCl. These results did not noticeably change in adsorption capacity during the three cycles. Using HCl (0.1 M), desorption of both metals was achieved up to 90% in three cycles. This work presented a long-term bioremediation approach for heavy metal pollutants in wastewater. This research could be seen as an interdisciplinary approach to large-scale heavy metal remediation. In addition, growing microalgae in wastewater produces animal feed and biodiesel. When compared to other conventional methods for environmental remediation and the manufacture of valuable products, the use of microalgae is a more efficient and cost-effective method.

Adsorption of Tetracycline and Ciprofloxacin from Aqueous Solution on Raw Date Palm Waste

AbstractRaw date palm waste was investigated as an adsorbent to remove tetracycline (TC) and ciprofloxacin (CIP) from water. Influence of pH, biosorbent dose, starting antibiotic concentration, contact time, temperature, and concentrations of different salts were examined. The pseudo‐second‐order model provided the best fit to the experimental data, while Langmuir and Dubinin‐Radushkevich isotherms were found to be the most suitable for TC and CIP adsorption at equilibrium, respectively. Thermodynamic parameters indicated that the process is spontaneous and endothermic. These findings suggest that this waste could be a cost‐effective and eco‐friendly adsorbent to remove antibiotics from wastewater.

Investigation of Effective Removal of Auramine O Dye by Pyracantha Coccinea Biosorbent: Isotherm and Kinetics

In this study, the effect of biosorbent dosage (0.1-0.4 g/L), dye pH (3.0-9.0) and initial dye concentration (50-500 mg/L) on synthetic Auramine O (AU-O) dye removal of biosorbent produced from Pyracantha coccinea (PC) plant by physical modification was investigated and the dye removal behavior of the biosorbent was investigated by kinetic and isotherm experiments. In the batch experiments, it was observed that as the adsorbent quantity was raised from 1 g/L to 4 g/L at a consistent dye concentration, the adsorption capacity declined from 69.25 mg/g to 22.73 mg/g. The adsorption capacities of AU-O dye at concentrations of 50 mg/L and 100 mg/L were determined to be 22.350 mg/g and 72.35 mg/g at 200 mg/L, respectively. The reason why there was no significant increase in adsorption capacity at higher dye concentrations (250-500 mg/L) was that at constant amount of biosorbent, the change in adsorption capacity was minimal since the active sites of the biosorbent reached saturation. The adsorption capacity was determined to be 26.512 mg/g, 38.74 mg/g, and 44.07 mg/g at pH:3.0, pH:4.88, and pH:7.0, respectively. It has been determined that the adsorption capacity achieved at pH 9.0 (44.21 mg/g) was nearly equivalent to the adsorption capacity observed under neutral pH conditions. The adsorption mechanism is best explained by the Langmuir isotherm (qm:123.10 mg/g and R2:0.990) and the pseudo-second-order kinetic models (R2: 0.985) in the adsorption isotherm and kinetic research.

Biosorption of Pd(II) from Aqueous Solution using Leaves of Moringa oleifera as a Low-cost Biosorbent

Palladium ion (Pd(II)) is one of the hazardous metal pollutants commonly found in industrial effluents and poses severe environmental and human health impacts. The present study has chosen the leaves of Moringa oleifera (L-MO) as a potential biosorbent for removing Pd(II) from the aqueous solution. Various parameters such as pH, biosorbent dose, and initial Pd(II) concentration were optimized for maximum removal of Pd(II) using standard protocols. The Fourier-transform infrared spectroscopy study was performed to identify the functional groups involved in Pd(II) biosorption mechanism. The analysis of FTIR spectra confirmed the involvement of functional groups such as C–O, C=O, C–H, and O–H in the biosorption of Pd(II) on the surface of L-MO. The biosorption of Pd(II) was highest at pH 6. The sorption equilibrium data were well-fitted with the Langmuir isotherm model (R2 = 0.9896). The highest adsorption capacity of L-MO was 41.15 mg/g. It is concluded that the L-MO could be used as a potentially low-cost novel biosorbent to remove Pd(II) from contaminated water.

Elucidating facile biosorptive eradication of enrofloxacin: Equilibrium, kinetics, reusability, cost estimation, and safe disposal

AbstractIn the current investigation, superheated steam activated green coconut shell (Cocos nucifera) biochar (PAGCSB) has been used in sorptive expulsion of the pharmaceutical micro‐pollutant enrofloxacin (ENX) from water. Through a number of progressive studies in batch sorption process, the influence of some crucial parameters are evaluated toward efficacious remediation of ENX laden aqueous media by PAGCSB. The parameters studied are: contact time (5–20 h); mixing intensity (100–190 rpm); pH (1–9); initial ENX concentration (5–35 mg/L); temperature (15–40°C); and biosorbent dosage (2–5 g/L). The maximum ENX removal is 91.92% by using ENX initial concentration 20 mg/L; pH 7; temperature 30°C; biosorbent dose 4 g/L; stirring speed 150 rpm; and contact period 16 h. The repeated usability of spent biochar has been assessed and found to be 69.91% even after the fifth cycle. The pseudo‐second order kinetic model provided the best fit to the kinetic data. The Langmuir model showed the finest suit to the isotherm data. Adsorption capacity of the biosorbent was observed to be 2.32 mg/g. The current study on biosorptive riddance of ENX revealed a good level of randomness in the thermodynamic process which is found to be exothermic in nature. A wide‐scale utilization of the developed biosorbent has been well‐substantiated by the cost estimation. Finally, the safe disposal of spent biosorbent has been studied in accordance with the World Health Organization safety guidelines. Hence, superheated steam activated green coconut shell derived biochar could be a cost‐effective and competent sorbent material for ENX eradication from contaminated water.

Surface engineered functional biomaterials for hazardous pollutants removal from aqueous environment

The issue of water contamination by heavy metal ions as highly persistent pollutants with harmful influence primarily on biological systems, even in trace levels, has become a great environmental concern globally. Therefore, there is a need for the use of highly sensitive techniques or preconcentration methods for the removal of heavy metal ions at trace levels. Thus, this research investigates a novel approach by examining the possibility of using pomegranate (Punica granatum) peel layered material for the simultaneous preconcentration of seven heavy metal ions; Cd(II), Co(II), Cr(III), Cu(II), Mn(II), Ni(II) and Pb(II) from aqueous solution and three river water samples. The quantification of the heavy metals was performed by the means of FAAS technique. The characterization of biomaterial was performed by SEM/EDS, FTIR analysis and pHpzc determination before and after the remediation process. The reusability study as well as the influence of interfering ions (Ca, K, Mg, Na and Zn) were evaluated. The conditions of preconcentration by the column method included the optimization of solution pH (5), flow rate (1.5 mL/min), a dose of biosorbent (200 mg), type of the eluent (1 mol/L HNO3), sample volume (100 mL) and sorbent fraction (<0.25 mm). The biosorbent capacity ranged from 4.45 to 57.70 μmol/g for the investigated heavy metals. The practical relevance of this study is further extended by novel data regarding adsorbent cost analysis (17.49 $/mol). The Punica granatum sorbent represents a highly effective and economical biosorbent for the preconcentration of heavy metal ions for possible application in industrial sectors.

Removal of heavy metals, turbidity and coliform from contaminated raw drinking water using Saccharomyces cerevisiae, the Baker's yeast

The efficiency of Saccharomyces cerevisiae (baker's yeast) was investigated for biosorption of Ni, Cu and Al, turbidity and total coliform reduction from raw drinking water and as coagulant aid with alum (aluminum sulphate). Optimization of metal biosorption (at 50 mg/L initial metal ion concentration) using dried baker's yeast was performed using different pH (1–7), bio-sorbent (yeast) dosage (0.02 –2.0 g/L) and contact time (5.0–90 min). S. cerevisiae exhibited high selectivity towards Cu removal compared to Al and Ni at pH 7, 0.5 g yeast dosage and 30 min contact time, which considered the optimum conditions. Concurrently with metal removal bioassay, baker's yeast was tested as a coagulant aid in a parallel assay. Addition of 1.5 mg/L baker's yeast to the optimum dose of alum (24 mg/L) enhanced turbidity removal reaching 95.43% compared to 90% achieved when alum was used alone. Also, total coliform (TC) was reduced by 92.86% from initial density of 280 CFU/100 mL in the raw water when 1.0 mg/L baker's yeast was added to the optimum alum compared to 67.86% with alum alone. Therefore, it is recommended to use baker's yeast as coagulant aid with alum as primary coagulant. Results of the present study confirmed the important role of the baker's yeast for the removal of heavy metals, turbidity and coliform bacteria associated with the raw drinking water at the tested area. Moreover, results exhibited high efficiency of baker's yeast as a coagulant aid in the improvement of the drinking water treatment process performance.

Live Biomass of Rigidoporus vinctus: A Sustainable Method for Decoloration and Detoxification of Dyes in Water.

In this study, white-rot fungus, Rigidoporus vinctus, collected from an unidentified fallen twig from Pathankot, Punjab, India, was used for biosorption of anionic Congo red and cationic Methylene blue dyes from an aqueous medium. The biosorption efficiency of the live biomass of Rigidoporus vinctus was investigated to optimize biosorbent dosage, process time, concentrations of dyes, and pH of solutions. The results indicated that Rigidoporus vinctus is more efficient than other reported bio-adsorbents for Congo red and Methylene blue dyes. The maximum biosorption activity of Rigidoporus vinctus for Congo red was found at pH 2, and that for Methylene blue was at pH 10, after 24 h of the reaction period. The process followed pseudo-second-order kinetics, which indicated that the interaction of both dyes to the adsorption sites on the surface of Rigidoporus vinctus was responsive to biosorption. The biosorption process could be well explained by the Langmuir isotherm for both dyes. The maximum monolayer biosorption capacity of Rigidoporus vinctus for Congo red and Methylene blue was observed to be 54.0 mg/g and 80.6 mg/g, respectively. The seed germination test was carried out, and it was assessed that the toxicity of dyes was reduced up to significant levels. Based on the present experimental findings, it can be concluded that biosorption using the live biomass of Rigidoporus vinctus can effectively decolorize dye-containing wastewater, thus reducing the hazardous effects of dyes on human beings.

Ability of Moringa Ore (Moringa Oleifera) As Biosorbent in Used Cooking Oil Processing

The results of this study stated that the use of activated moringa ore biosorbents had a great influence on the quality of cooking oil both physically and chemically. The results of data analysis based on variations in contact time and dose variations can show that free fatty acid levels have decreased but are not in accordance with the stipulated SNI, namely 0.17%. Activation of Moringa ore using Sodium Hydroxide (NaOH) can reduce the levels of free fatty acids in used cooking oil. Variation of biosorbent contact time can affect the decrease in fatty acid levels, which occurs at the optimum contact time of 90 minutes, the free fatty acid percentage of 0.17% is not in accordance with SNI. Variations in biosorbent doses can also affect the increase in free fatty acid levels, namely the optimum dose of 1.00-gram percentage of free fatty acids decreased by 0.17% not according to SNI. Variations in contact time and variations in optimum doses of biosorbents can also affect color organoleptic tests and the smell of used cooking oil. Where the results of each respondent's statement that 95% of the refined oil using Moringa ore biosorbent are similar to new cooking oil, namely with a bright yellow color. The method used in this study is a quantitative method by conducting experiments on the subjects to be studied and used as a reference for finding and obtaining data directly through observation or experimentation

Investigation of kinetic, isotherm and adsorption efficacy of thorium by orange peel immobilized on calcium alginate

In this research work the thorium uptake on immobilized protonated orange peel was studied in a batch system. The effects of effective parameters such as biosorbent dosage, initial metal ion concentration, and contact time on the biosorption of thorium were analyzed. The biosorption capacity of the immobilized orange peel for thorium at optimal conditions of initial pH 3.8, biosorbent dosage 8 g/L, and initial thorium concentration 170 mg/L was found to be 18.65 mg/g. According to the results of contact time, the biosorption process reached equilibrium after around 10 h of contact. Investigation of the kinetics showed that the biosorption of thorium onto immobilized orange peel follows the pseudo-second-order model. The Langmuir and Freundlich isotherms were used to model the experimental equilibrium data. The results showed better agreement by the Langmuir isotherm. The maximum absorption capacity of immobilized protonated orange peel for thorium adsorption was predicted by the Langmuir isotherm at 29.58 mg/g.

Potential use of extracellular polymeric substances (EPS) of Bacillus subtilis for biosorption of mercury produced from soil-washing effluent

Extracellular polymeric substances (EPS) can be used as an effective biosorbent for removing heavy metals from soil washing effluent. In this research, Bacillus subtilis was used as an EPS-producing bacteria with a yield of bound EPS of 0.6 mg/g biomass with protein and polysaccharide content of 199 mg/g EPS and 8.8 mg/g EPS, respectively. The maximum biosorption capacities for mercury in artificial wastewater using bound EPS and dead biomass of Bacillus subtilis as biosorbents were 9.32 mg/g and 6.04 mg/g, respectively, at a biosorbent dose of 0.1 g/100 mL. Biosorption using Bacillus subtilis fitted the Langmuir isotherm, while biosorption using bound EPS fitted the Freundlich isotherm. The biosorption process followed a pseudo-second-order kinetic model for both biosorbents. Bound EPS was also feasible to treat soil washing effluent with a biosorption capacity of 2.21 mg/g of mercury. The use of bound EPS could effectively remove mercury from wastewater.

Development and Characterization of Biosorbent Film from Eggshell/Orange Waste Enriched with Banana Starch.

The conversion of waste into a valuable product is regarded as a promising alternative to relieving the burden of solid waste management and could be beneficial to the environment and humans. This study is focused on utilizing eggshell and orange peel enriched with banana starch to fabricate biofilm via the casting technique. The developed film is further characterized by field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The physical properties of films, including thickness, density, color, porosity, moisture content, water solubility, water absorption, and water vapor permeability, were also characterized. The removal efficiency of the metal ions onto film at different contact times, pH, biosorbent dosages, and initial concentration of Cd(II) were analyzed using atomic absorption spectroscopy (AAS). The film's surface was found to have a porous and rough structure with no cracks, which can enhance the target analytes interactions. EDX and XRD analyses confirmed that eggshell particles were made of calcium carbonate (CaCO3), and the appearance of the main peak at 2θ = 29.65° and 2θ = 29.49° proves the presence of calcite in eggshells. The FTIR indicated that the films contain various functional groups, such as alkane (C-H), hydroxyl (-OH), carbonyl (C=O), carbonate (CO32-), and carboxylic acid (-COOH) that can act as biosorption materials. According to the findings, the developed film exhibits a notable enhancement in its water barrier properties, thereby leading to improved adsorption capacity. The batch experiments showed that the film obtained the maximum removal percentage at pH = 8 and 6 g of biosorbent dose. Notably, the developed film could reach sorption equilibrium within 120 min at the initial concentration of 80 mg/L and remove 99.95% of Cd(II) in the aqueous solutions. This outcome presents potential opportunities for the application of these films in the food industry as both biosorbents and packaging materials. Such utilization can significantly enhance the overall quality of food products.

Optimized removal of cadmium, copper and lead from wastewater by biosorption using cabbage waste and Box-Behnken design (BBD)

In this study a Box-Behnken (BBD) design was applied to optimize biosorption of copper, cadmium, and lead using cabbage waste. The effects of operating parameters including initial pH, biosorbent dosage, contact time, and heavy metal concentration were determined by BBD. The maximum biosorption removal efficiency was achieved at pH 4, 300 min operation time, 1.5 g/250 mL biosorbent dosage, and an initial heavy metal concentration of 25 mg/L. The maximum removal efficiencies were 77.23% for Cu, 93.10% for Pb, and 67.19% for Cd at optimal conditions. The cabbage waste was found to be an effective, sustainable, locally available, and environmentally friendly biosorbent for removing heavy metals from aqueous solution.

Biosorption of Triphenyl Methane Dyes (Malachite Green and Crystal Violet) from Aqueous Media by Alfa (Stipa tenacissima L.) Leaf Powder.

This study includes the characterization and exploitation of an abundant agricultural waste in Algeria, Alfa (Stipa tenacissima L.) leaf powder (ALP) as a biosorbent for the removal of hazardous triphenylmethane dyes, malachite green (basic green 4) and crystal violet (basic violet 3), from aqueous media under various operating conditions in batch mode. The effect of experimental parameters such as initial dye concentration (10-40 mg/L), contact time (0-300 min), biosorbent dose (2.5-5.5 g/L), initial pH (2-8), temperature (298-328 K), and ionic strength on dye sorption was investigated. The results of both dyes show that the increase in initial concentration, contact time, temperature, and initial pH of solution leads to an increase in biosorbed quantity, unlike the effect of ionic strength. The biosorption kinetics for triphenylmethane dyes on ALP was analyzed by pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models proposed by the Weber-Morris equation. Equilibrium sorption data were analyzed by six isotherms, namely the Langmuir, Freundlich, Harkins-Jura, Flory-Huggins, Elovich, and Kiselev isotherms. The thermodynamic parameters were evaluated for both dyes. The thermodynamic results suggest that both dyes' biosorption is a typical physical process, spontaneous and endothermic in nature.

Intensification of strontium (II) ion biosorption on Sargassum sp via response surface methodology

A batch system was employed to investigate the biosorption of strontium (II) on Sargassum sp. The biosorption of strontium on Sargassum sp was studied with response surface methodology to determine the combined effect of temperature, initial metal ion concentration, biomass treatment, biosorbent dosage and pH. Under optimal conditions, the algae's biosorption capacity for strontium (initial pH 7.2, initial strontium concentration 300 mg/l for Mg-treated biomass and biosorbent dosage 0.1 g in 100 mL metal solution) was measured at 103.95 mg/g. In our analysis, equilibrium data were fitted to Langmuir and Freundlich isotherms. Results show that the best fit is provided by the Freundlich model. Biosorption dynamics analysis of the experimental data indicated that strontium (II) was absorbed into algal biomass in accordance with the pseudo-second-order kinetics model well.