Biosorption Capacity Research Articles

Bioremediation potential of microalgae for copper ion from wastewater and its impact on growth and biochemical contents: equilibrium isotherm studies

The use of microalgae to remediate heavy metal-contaminated wastewater has attracted more and more interest. In this investigation, the green microalgae Chloroidium ellipsoideum and Desmodesmus subspicatus were used to study copper uptake from nutrient media and its effect on algal growth and metabolism. The growth of C. ellipsoideum and D. subspicatus generally decreased with increasing copper concentrations. There was a decrease in the carbohydrate content of C. ellipsoideum, but an increase was observed in D. subspicatus by treatment with various copper concentrations. Low concentrations of copper helped to increase the protein content of C. ellipsoideum, but a decline in protein content was reported for D. subspicatus. By increasing the copper concentrations, an increase in the free amino acids and a decrease in the total lipid content of C. ellipsoideum and D. subspicatus were recorded. At 0.1 mgl–1 copper concentration, pH of 6.8, and algal dose of 1 g L−1, the maximum biosorption capacity of C. ellipsoideum was 0.398 mg g−1, corresponding to the maximum reduction of 68.66% of Cu2+, and 0.396 mg/g for D. subspicatus, corresponding to the maximum reduction of 59.52%. The Langmuir, Freundlich, Temkin and Dubinin–Radushkevich models were applied to describe the isothermal biosorption of Cu2+ ions in studied algae. The Dubinin–Radushkevich model indicated that the copper biosorption mechanism was physical in nature. Cu2+ has a greater affinity for D. subspicatus than C. ellipsoideum, suggesting that C. ellipsoideum was relatively more resistant to Cu2+ toxicity than D. subspicatus. Moreover, FT-IR analysis revealed that carboxyl, amide, amino, carbonyl, hydroxyl, methyl and alkyl groups were the key groups responsible for the biosorption process. Therefore, D. subspicatus and C. ellipsoideum are efficient biosorbents for Cu2+ and can be used as biosorbents for heavy metals removal from wastewater.

Biosorption of arsenic (III) from aqueous solution using calcium alginate immobilized dead biomass of Acinetobacter sp. strain Sp2b

This study presents a novel biosorbent developed by immobilizing dead Sp2b bacterial biomass into calcium alginate (CASp2b) to efficiently remove arsenic (AsIII) from contaminated water. The bacterium Sp2b was isolated from arsenic-contaminated industrial soil of Punjab, a state in India. The strain was designated Acinetobacter sp. strain Sp2b as per the 16S rDNA sequencing, GenBank accession number -OP010048.The CASp2b was used for the biosorption studies after an initial screening for the biosorption capacity of Sp2b biomass with immobilized biomass in both live and dead states. The optimum biosorption conditions were examined in batch experimentations with contact time, pH, biomass, temperature, and AsIII concentration variables. The maximum biosorption capacity (qmax = 20.1 ± 0.76 mg/g of CA Sp2b) was obtained at pH9, 35 ̊ C, 20 min contact time, and 120 rpm agitation speed. The isotherm, kinetic and thermodynamic modeling of the experimental data favored Freundlich isotherm (R2 = 0.941) and pseudo-2nd-order kinetics (R2 = 0.968) with endothermic nature (ΔH° = 27.42) and high randomness (ΔS° = 58.1).The scanning electron microscopy with energy dispersive X-ray (SEM–EDX) analysis indicated the As surface binding. The reusability study revealed the reasonable usage of beads up to 5 cycles. In conclusion, CASp2b is a promising, efficient, eco-friendly biosorbent for AsIII removal from contaminated water.

Assessing the Suitability of Green Algae (Chlorella Sorokiana) as Biosorbent for Removal of Cu (II) and Zn (II) Ions from Synthetic Wastewater in a Batch System

Heavy metal contamination in wastewater poses a significant threat to environmental and human health. This study investigated the potential of Chlorella sorokiana, a green alga, as a biosorbent for Cu (II) and Zn (II) removal from synthetic wastewater. Batch experiments were conducted at 28°C, pH 6, and a contact time of 60 minutes. Chlorella sorokiana displayed promising biosorption capacity, removing 85% and 75% of Cu (II) and Zn (II), respectively. Further optimization revealed enhanced removal efficiencies at pH 5 (88.5% Cu (II) and 82% Zn (II)) and a biosorbent dosage of 0.5 g/L (90.7% Cu (II) and 87.1% Zn (II)). These findings demonstrate the efficacy of Chlorella sorokiana as a biosorbent for heavy metal remediation. This research highlights the potential of biosorption as a sustainable and environmentally friendly approach for wastewater treatment, offering a promising solution for mitigating heavy metal pollution.

Cadmium biosorption: Lake waters in Bengaluru-mitigation of cadmium-induced oxidative stress by Selaginella bryopteris

ABSTRACT Heavy metals cause alarming levels of environmental and health problems and among them Cadmium has become a threat to organisms and natural resources like soil and water alike. It accumulates in living systems thereby causing oxidative stress. Efforts are made for bioremediation of heavy metals by employing biosorption, which is a well-known economic method for removal and in the current study Selaginella bryopteris was used as biosorbent. The biosorption capacity was optimized by its physicochemical parameters such as pH, dosage, contact time, and temperature. Cadmium-induced Reactive Oxygen Species levels and the antioxidant potential of S. bryopteris in ameliorating them were studied in Drosophila melanogaster. Water-quality analysis was performed using Chemical Oxygen Demand(COD) and Biological Oxygen Demand (BOD) and effect of S.bryopteris on these parameters were also analyzed. Further the concentration of Cadmium via colorimetric assay and Atomic Absorption Spectroscopy(AAS) was employed to quantify the Cadmium in lake water samples before and after treatment with biosorbent. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) were performed to characterize the surface properties for adsorptive removal of metal ions, and antioxidant studies were conducted to assess the role of S. bryopteris in suppressing oxidative stress.

EVALUATION OF THE BIOSORPTION OF Mn²⁺ AND Zn²⁺ BY PASSION FRUIT PEEL: STUDY OF DOSAGE AND CONTACT TIME

Objective: The objective of this study is to investigate he effectiveness of Mn2+ and Zn2+ biosorption by passion fruit peel as a sustainable and economically viable alternative to the biosorption process. Method: The methodology adopted for this research comprises the characterization of the biomass and batch tests. Tests were carried out with different masses of biomass in standard solutions of the metals investigated. The biosorption capacity of the biomass and the removal efficiency were calculated based on the differences in concentration of the metal ions. Results and Discussion: The results obtained revealed that the biomass showed high efficiency (close to 100%) for both cations. The contact time of 30 minutes was sufficient to reach equilibrium in the biosorption capacity of the metals, indicating the speed and effectiveness of the process. Research Implications: The practical and theoretical implications of this research provide valuable information on the application of passion fruit peel as a biosorbent in the removal of potentially toxic metals from contaminated wastewater. These results may influence practices in the field of environmental remediation and environmental engineering, as well as in agro-industrial waste management. Originality/Value: This study contributes to the literature by highlighting the originality of using passion fruit peel in natura as a biosorbent, presenting an innovative and sustainable approach to the remediation of contaminated effluents. The high efficiency of ion removal with low biomass dosages and short contact times adds knowledge to the field of biosorption using agro-industrial waste.

An overview on the key advantages and limitations of batch and dynamic modes of biosorption of metal ions

Water purification using adsorption is a crucial process for maintaining human life and preserving the environment. Batch and dynamic adsorption modes are two types of water purification processes that are commonly used in various countries due to their simplicity and feasibility on an industrial scale. However, it is important to understand the advantages and limitations of these two adsorption modes in industrial applications. Also, the possibility of using batch mode in industrial scale was scrutinized, along with the necessity of using dynamic mode in such applications. In addition, the reasons for the necessity of performing batch adsorption studies before starting the treatment on an industrial scale were mentioned and discussed. In fact, this review article attempts to throw light on these subjects by comparing the biosorption efficiency of some metals on utilized biosorbents, using both batch and fixed-bed (column) adsorption modes. The comparison is based on the effectiveness of the two processes and the mechanisms involved in the treatment. Parameters such as biosorption capacity, percentage removal, and isotherm models for both batch and column (fixed bed) studies are compared. The article also explains thermodynamic and kinetic models for batch adsorption and discusses breakthrough evaluations in adsorptive column systems. The review highlights the benefits of using convenient batch-wise biosorption in lab-scale studies and the key advantages of column biosorption in industrial applications.

A promising approach for the removal of hexavalent and trivalent chromium from aqueous solution using low-cost biomaterial.

Heavy metal pollution is an enduring environmental challenge that calls for sustainable and eco-friendly solutions. One promising approach is to harness discarded plant biomass as a highly efficient environmental friendly adsorbents. In this context, a noteworthy study has spotlighted the employment of Euryale ferox Salisbury seed coat (E.feroxSC) for the exclusion of trivalent and hexavalent chromium ions. This study aims to transform discarded plant residue into a novel, environmentally friendly, and cost-effective alternative adsorbent, offering a compelling alternative to more expensive adsorption methods. By repurposing natural materials, we can contribute to mitigating heavy-metal pollution while promoting sustainable and economically viable solutions in environmental remediation. The effect of different parameters, i.e., chromium ions' initial concentration (5-25mg L-1), solution pH (2-7), adsorbent dosage (0.2-2.4g L-1), contact time (20-240min), and temperature (298-313K), were investigated. E.feroxSC proved highly effective, achieving 96.5% removal of Cr(III) ions at pH 6 and 97.7% removal of Cr(VI) ions at pH 2, with a maximum biosorption capacity of 18.33mg/g for Cr(III) and 13.64mg/g for Cr(VI), making it a promising, eco-friendly adsorbent for tackling heavy-metal pollution. The adsorption process followed the pseudo-second-order kinetic model, aligning well with the Langmuir isotherm, exhibited favorable thermodynamics, and was characterized as feasible, spontaneous, and endothermic with physisorption mechanisms. The investigation revealed that E.feroxSC effectively adsorbed Cr(VI) which could be rejuvenated in a basic solution with minimal depletion in its adsorption capacity. Conversely, E.feroxSC's adsorption of Cr(III) demanded rejuvenation in an acidic milieu, exhibiting comparatively less efficient restoration.

Influential lead uptake using dried and inactivated-fungal biomass obtained from Panaeolus papilionaceus: biological activity, equilibrium, and mechanism

AbstractIn this study, the use of fungal (Panaeolus papilionaceus) biomass as a biosorbent was investigated to effectively remove Pb2+ ions from aquatic medium. The removal of Pb2+ ions using a fungal biosorbent was examined in a batch system in terms of initial solution pH, temperature, time, and initial Pb2+ concentration. Optimal operating conditions for biosorption of Pb2+ ions; pH: 4.5, T: 25 °C, and t: 24 h. The max biosorption capacity for Pb2+ ions was found to be 31.2 mg g−1 from the Langmuir model. Thermodynamic studies showed that Pb2+ ions biosorption into fungal biomass was possible, spontaneous, and endothermic. Additionally, the antimicrobial activity and antibiofilm activity of the extract of fungus were also investigated. It was determined that the fungal extract did not have antimicrobial properties. On the other hand, the extract has been shown to have the potential to prevent biofilm formation. 1 mg of the extract prevented the biofilm formation of Staphylococcus aureus by 87.85%. It has been observed that the biosorption mechanism of Pb2+ ions into fungal biomass includes the steps of surface biosorption, film diffusion, and intra-particle diffusion.

Enhancing the Biosorption Potential of Pichia kluyveri FM012 for 4-Bromophenols

AbstractThe use of toxic and persistent pesticides in agriculture results in serious and lasting environmental impacts. Although traditional methods, such as physical and chemical reclamation, yield the best results, treating these contaminants requires a high cost and expertise. Therefore, this study focuses on bioremediation recovery, which is more efficient, economical, and safer for removal. In this case, the newly isolated potential of Pichia kluyveri FM012 in degrading 4-bromophenol was investigated. The impact of optimized parameters such as agitation, pH, nitrogen, and carbon source were also studied. After extensive testing, the best optimal degradation occurred at pH 5 with a stirrer speed of 150 rpm. Glucose and yeast performed the best compared to other carbon and nitrogen sources. The Langmuir model predicted the maximum biosorption capacity (qm = 38.46 mg/g biomass), but the Freundlich model provided a better value of R2 = 0.999. The pseudo-second-order kinetic model was fitting for the study of biosorption kinetics. The FTIR spectrum revealed the presence of asymmetric and symmetric vibrations of the aromatic ring and was assigned to C = C or C = O. Fungi showed biosorption ability across broad functional groups. These results provide interesting information about the ability of Pichia kluyveri FM012 and its potential applications for remediating resistant pesticides.

Application of Aptenia cordifolia powder as a biosorbent for methylene blue retention from an aqueous medium: Isotherm, kinetic, and thermodynamic investigations

In this study, Aptenia cordifolia powder was utilized as a biosorbent material to effectively treat a synthetic aqueous solution polluted with methylene blue. The characterization of Aptenia cordifolia was conducted according to several analyses, including Fourier transforms infrared, scanning electron microscopy, the point of zero charge and energy dispersive X-ray. The retention process was investigated considering several factors including biosorbent mass, contact time, initial solution pH, temperature, and the initial concentration of methylene blue. The results obtained indicate that the optimal dose of adsorbent was 2 g.L−1. The equilibrium time was approximately 120 min, and the biosorption capacity of the biosorbent increases with an increase in pH. The pseudo-second-order model describes adequately the retention of methylene blue using Aptenia cordifolia. The Langmuir model proved to be more applicable in the analysis of the isotherm data, indicating a maximum retention amount of 51.82 mg.g−1. Moreover, the removal of methylene blue was thermodynamically endothermic, spontaneous, and favorable. These findings demonstrate the potential of Aptenia cordifolia biomass as an effective biosorbent for the treatment of dyes contaminated effluents.

Investigation and Optimization of Biosorbent Capacities of Some Plants Used in Daily Life

In this study, sage, chamomile, and tarragon leaves, which are used as spices and consumed as beverages in daily life, were considered as different biosorbents that can be used in water purification by biosorption. At the same time, the effects of the parameters of initial dye concentration (10-200 mg/L), temperature (20-50 ⁰C) and contact time (0-120 min) on biosorption capacity were investigated. The biosorption processes were found to follow Freundlich isotherm and pseudo-second order (PSO) reaction kinetics. In the study, the process was also modeled using multi-tree evolutionary computation based automatic programming (AP) methods. The methods used initial dye concentration, temperature, and contact time as variables. According to the simulation results, these methods obtained nonlinear mathematical models of the processes with R^2 values as high as 0.99 for each biosorbent. By providing the most accurate models to accurately predict biosorption capacity, this study will make a significant contribution to the field of water treatment using experimental and AP methods.

Toxicity, physiological response, and biosorption mechanism of Dunaliella salina to copper, lead, and cadmium.

Heavy metal pollution has become a global problem, which urgently needed to be solved owing to its severe threat to water ecosystems and human health. Thus, the exploration and development of a simple, cost-effective and environmental-friendly technique to remove metal elements from contaminated water is of great importance. Algae are a kind of photosynthetic autotroph and exhibit excellent bioadsorption capacities, making them suitable for wastewater treatment. The effects of heavy metals (copper, lead and cadmium) on the growth, biomolecules accumulation, metabolic responses and antioxidant response of Dunaliella salina were investigated. Moreover, the Box-Behnken design (BBD) in response surface methodology (RSM) was used to optimize the biosorption capacity, and FT-IR was performed to explore the biosorption mechanism of D. salina on multiple heavy metals. The growth of D. salina cells was significantly inhibited and the contents of intracellular photosynthetic pigments, polysaccharides and proteins were obviously reduced under different concentrations of Cu2+, Pb2+ and Cd2+, and the EC50 values were 18.14 mg/L, 160.37 mg/L and 3.32 mg/L at 72 h, respectively. Besides, the activities of antioxidant enzyme SOD and CAT in D. salina first increased, and then descended with increasing concentration of three metal ions, while MDA contents elevated continuously. Moreover, D. salina exhibited an excellent removal efficacy on three heavy metals. BBD assay revealed that the maximal removal rates for Cu2+, Pb2+, and Cd2+ were 88.9%, 87.2% and 72.9%, respectively under optimal adsorption conditions of pH 5-6, temperature 20-30°C, and adsorption time 6 h. Both surface biosorption and intracellular bioaccumulation mechanisms are involved in metal ions removal of D. salina. FT-IR spectrum exhibited the main functional groups including carboxyl (-COOH), hydroxyl (-OH), amino (-NH2), phosphate (-P=O) and sulfate (-S=O) are closely associated with the biosorption or removal of heavy metalsions. Attributing to the brilliant biosorption capacity, Dunaliella salina may be developed to be an excellent adsorbent for heavy metals.

Evaluation of biosorbent properties of Teucrium polium seeds in Rhodamine B removal; isotherm, kinetic, thermodynamic studies

Water pollution is a major environmental concern worldwide, particularly due to industrial paint waste. Therefore, treating wastewater from various industrial sources is crucial to restoring environmental quality. In this study, a batch biosorption system was used to investigate the biosorption of Rhodamine B (RhB), a highly toxic dye, on Teucrium polium seeds (TPS). The study examined the effects of different parameters such as initial dye concentration, contact time, initial pH, temperature, and biosorbent amount on RhB removal. To determine the physicochemical properties of TPS, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and zero charge point (PZC) characterization analyses were performed. The maximum biosorption capacity of TPS at pH = 5.5 and 25 °C was found to be 4.18 mg g−1. The study found that the removal rate of RhB was 93.3% at an initial RhB dye concentration of 200 mg L−1. The experimental data showed that the Langmuir isotherm model (R 2 = 0.940) was the most compatible model for biosorption, while the biosorption kinetic mechanism proceeded through the pseudo-second-order (PSO) kinetic model (R 2 = 0.925). Additionally, the study found that intraparticle diffusion, pore diffusion, and film diffusion were effective in the RhB biosorption rate mechanism. Thermodynamic studies revealed that the biosorption was endothermic (ΔH0>0), spontaneous (ΔS0>0), and entropy-increasing (ΔG0 <0). As a result, TPS, which has suitable adsorbent properties for RhB, can be recommended as a new, cost-effective, abundant potential biosorbent.

Integrating biosorption and machine learning for efficient remazol red removal by algae-bacteria co-culture and comparative analysis of predicted models

This research investigates into the efficacy of algae and algae-bacteria symbiosis (ABS) in efficiently decolorizing Remazol Red 5B, a prevalent dye pollutant. The investigation encompasses an exploration of the biosorption isotherm and kinetics governing the dye removal process. Additionally, various machine learning models are employed to predict the efficiency of dye removal within a co-culture system. The results demonstrate that both Desmodesmus abundans and a composite of Desmodesmus abundans and Rhodococcus pyridinivorans exhibit significant dye removal percentages of 75 ± 1% and 78 ± 1%, respectively, after 40 min. The biosorption isotherm analysis reveals a significant interaction between the adsorbate and the biosorbent, and it indicates that the Temkin model best matches the experimental data. Moreover, the Langmuir model indicates a relatively high biosorption capacity, further highlighting the potential of the algae-bacteria composite as an efficient adsorbent. Decision Trees, Random Forest, Support Vector Regression, and Artificial Neural Networks are evaluated for predicting dye removal efficiency. The Random Forest model emerges as the most accurate, exhibiting an R2 value of 0.98, while Support Vector Regression and Artificial Neural Networks also demonstrate robust predictive capabilities. This study contributes to the advancement of sustainable dye removal strategies and encourages future exploration of hybrid approaches to further enhance predictive accuracy and efficiency in wastewater treatment processes.

Arsenic Species Distribution and Toxicity in the Environment, Bioaccumulation, Biomethylation and Bioremediation by Microalgae: A Review

Arsenic (As) is a noxious metalloid that has been designated a priority pollutant and is present in the environment as a consequence of both anthropogenic and natural processes. Its toxicity in environmental and biological systems depends strongly on the chemical species. Interest in arsenic and microalgae interactions is important because microalgae are at the base of the aquatic food chain, are used in animal nutrition and has potential for As phytoremediation. This paper reviewed the current information on As species distribution in the environment especially as it relates to its toxicity to microalgae as well as its bioaccumulation, biomethylation and bioremediation by microalgae using appropriate methods. Information obtained revealed that Microalgae have evolved mechanisms for dealing with As in the environment with arsBHC operon mediating the reduction and extrusion of arsenite from the cells. They accumulate large amounts of arsenic from their surroundings which could lead to toxicity, As excretion from cells, reduction, methylation or complexation with metal binding peptides like glutathione and phytochelatins. This has made them suitable as ecological indicators to give an indication of As bioavailability and also in possible applications for the process of As remediation. Microalgae are been proposed for bioremediation purposes in aquatic environment since they show a high capacity for biosorption and bioconcentration of As and most importantly since they are able to methylate inorganic As to non-toxic organic and volatile As.

A comparative study on heavy metal (cadmium) tolerance and biosorption capacity of locally isolated lactic acid bacteria

Heavy metals (HM) have less biological role but show extreme toxicity in living systems. Lactic acid bacteria (LAB) are beneficial microorganisms, some of which have the ability to chelate HM and may be used to treat heavy metals poisoning. The aim of the current study was to select and identify Cd-removing probiotic LAB strains, for future pharmaceutical application. Seventeen LAB strains, from human excretions and animal fecal matter, were initially verified for their probiotic properties. The strains which could survive in the presence of Cd (≥100 ppm) were selected. The metal removal efficiency of isolates was compared, through atomic absorption spectrophotometry (AAS), by measuring the reduction in Cd contents of CdCl2 5 mg/L (3.05 ppm of Cd) supplemented broth following 24 h culturing of the strains. The Cd reduction of 38–75% was recorded in culture broth. The Cd removal ability significantly varied (p < 0.05) with microbial surface charge, incubation period, temperature and pH of media. Levilactobacillus brevis MW362790 and Pediococcus pentosaceus MT323062, identified through 16S rRNA gene sequencing, were recognized as strong Cd chelators. These strains may have application in pharmaceutical or agriculture (farm animals) for protection against cadmium toxicity. Further studies are suggested on in vivo metal detoxification potential.

A synergistic integration of life cycle assessment and response surface methodology to optimize grape stalk waste-based biosorption for effective Cd(II) removal

In order to remove Cd(II) ions from aqueous solutions, this research suggests an in-depth study on a laboratory scale for the efficient and sustainable removal of Cd(II) in aqueous solution using wine industry grape stalk waste. The maximum biosorption capacity that was achieved was 84.74 mg/g for the Langmuir isotherm model. The kinetic studies revealed that the biosorption data were better explained by a pseudo-second order model. By using the response surface method with desirability functions, the optimal variables were determined for three optimization scenarios. The first optimization scenario yielded the highest percentage of cadmium removal, reaching 87.75%. The goal of that scenario was intended to obtain the maximum percentage of cadmium removal while minimizing the cost of the process. In this scenario, the greatest environmental impact was on the marine aquatic ecotoxicity (2.685 kg 1.4 DB eq.) with a power consumption of 27.05 W. Furthermore, the values for the input variables were an initial cadmium concentration of 0.6 mg/l, pH of 7.5, stirring time of 10 min, stirring speed of 100 rpm, a process temperature of 15 °C, and a dose of grape stalk of 0.50 g. The experimental and predicted findings agree. This suggests that grape stalk waste has potential applications as a biosorbent for the removal of Cd(II) ions from aqueous solution.

Soil Contamination by Heavy Metals and Radionuclides and Related Bioremediation Techniques: A Review

The migration of heavy metals and radionuclides is interrelated, and this study focusses on the interaction and complex influence of various toxicants. The rehabilitation of radioactively contaminated territories has a complex character and is based on scientifically supported measures to restore industrial, economic, and sociopsychological relations. We aim for the achievement of pre-emergency levels of hygienic norms of radioactive contamination of output products. This, in its sum, allows for further economic activity in these territories without restrictions on the basis of natural actions of autoremediation. Biosorption technologies based on bacterial biomass remain a promising direction for the remediation of soils contaminated with radionuclides and heavy metals that help immobilise and consolidate contaminants. A comprehensive understanding of the biosorption capacity of various preparations allows for the selection of more effective techniques for the elimination of contaminants, as well as the overcoming of differences between laboratory results and industrial use. Observation and monitoring make it possible to evaluate the migration process of heavy metals and radionuclides and identify regions with a disturbed balance of harmful substances. The promising direction of the soil application of phosphogypsum, a by-product of the chemical industry, in bioremediation processes is considered.

Biosorption of Cu(II) Ions by Water Hyacinth Leaf Powder: Process Performance, Kinetics, and Biosorption Isotherm

The water hyacinth leaf powder (WH) was used to adsorb Cu(II) from wastewater. The WH was modified through sulfuric acid (A-WH) and sodium hydroxide (B-WH) treatments. The biosorption was studied with various initial pH, initial Cu(II) concentrations, and biosorp-tion time. The results show that the biosorption capacities of the biosorbents increase with the initial Cu(II) concentration. The optimum pH for the biosorption was 7.5, 7.0, and 7.5 for the WH, A-WH, and B-WH, respectively. The SEM images of the raw and treated WH revealed that alkali treatment could remove lignin more than the acid treatment, leaving more macropores in the B-WH than in the A-WH. The acid and alkali treatments to the WH leaf increase the biosorption capacity of the WH for Cu (II). The pseudo-second-order kinetic model can represent the dynamic behavior of the biosorption better than the pseudo-first-order model. The Langmuir model is better than the Freundlich model for describing the biosorption isotherm. The maximum biosorption capacities of the biosorbents predicted by the Langmuir model were 14.92 mg g−1, 18.32 mg g−1, and 23.27 mg g−1 for WH, A-WH, and B-WH, respectively.

Bio-sorption capacity of cadmium and zinc by Pseudomonas monteilii with heavy-metal resistance isolated from the compost of pig manure

The tolerance of Pseudomonas monteilii X1, isolated from pig manure compost, to Cd and Zn, as well as its capacity for biosorption, were investigated. The minimum inhibitory concentrations (MIC) of Cd and Zn for the strain were 550 mg/L and 800 mg/L, respectively. Untargeted metabolomics analysis revealed that organic acids and derivatives, lipids and lipid-like molecules, and organic heterocyclic compounds were the main metabolites. The glyoxylate and dicarboxylate metabolism pathway were significantly enriched under Cd2+ stress. The isothermal adsorption and adsorption kinetics experiments determined that the strain had adsorption capacities of 9.96 mg/g for Cd2+ and 23.4 mg/g for Zn2+. Active groups, such as hydroxyl, carboxyl, and amino groups on the cell surface, were found to participate in metal adsorption. The strain was able to convert Zn2+ into Zn3(PO4)2·4H2O crystal. Overall, this study suggested that Pseudomonas monteilii has potential as a remediation material for heavy metals.