Biosorption Of Metals Research Articles

Bioadsorption by Coffee Leaves in Poluted River Mantaro Water at Central Peru

The biosorption of heavy metals is the property of some types of biomass, a process that captures or accumulates metal ions, allowing their removal or immobilization. The present study was carried out in the Mantaro river, following the recommendations of the ANA (National Water Authority), the experimental process was carried out in the laboratories of the Universidad Continental and the Volcan Mining Company, for this purpose the drying of the coffee leaves of the species (Caturra-arabic coffea) and its subsequent grinding, then it was added in 4 different proportions for samples of 250 ml of water. The first results showed that the water contains lead (0.1 mg/l), copper (4.12 mg/l), iron (0.01 mg/l) and zinc (0.42 mg/l) with a pH (7.53) and electrical conductivity (67μS).which are not recommended according to the Environmental Quality Standards, after adding the coffee leaf allowing it to act in a period of 48 hours, the best result was with the second sample adsorbing lead (0%), copper (95.15%), iron (0%) and zinc (52.38%) with a pH of 7.05 and electrical conductivity (664μS). Coffee leaves were more effective in reducing copper by up to 95.15%.

Native Bacteria Isolated from Djebel Onk Deposits (Algeria) Reveal Efficient Metal Biosorption Properties

Native Bacteria Isolated from Djebel Onk Deposits (Algeria) Reveal Efficient Metal Biosorption Properties

Bioremediation Strategies for Mitigation of Heavy Metals: A Critical Review

In normal conditions plants require heavy metals for growth but their accumulation inn bioavailability form in soil and water has harmful effects on all biological systems. The increasing release of HMs from industrial discharge and other anthropogenic activities are threatening sustainable agricultural development, food supply and dairy industry. Under such conditions heavy metal (HM) stress is one of the most destructive abiotic stresses for plants. Anthropogenic activities are the main source of heavy metal (HM) accumulation. Industrial pollution of both water bodies and soil mainly consists of accumulation of Cr, Ni, Cu, Zn, Cd, Pb, Hg, and As. These heavy metals (HMs) non-biodegradable pollutants present in soil and water are not easy to metabolize and their concentration in soil and water increases with time. The conventional methods for removal of heavy metals from the environment involve high costs and are not eco-friendly. In contrast to this phytoremediation is an eco-friendly approach and it can be considered as an alternative to the traditional methods in terms of their cost-effectiveness and maximum recovery of the metal ions. Microbes have greater metal biosorption capacities and various mechanisms of metal sequestration. This review focuses on various aspects of phytoremediation including genetic engineering and microbe-assisted approaches.

Chlorella vulgaris meets TiO2 NPs: Effective sorbent/photocatalytic hybrid materials for water treatment application

A new class of bio-nano hybrid catalyst useable in downstream wastewater treatment was developed. We combined the sorption potentialities of Chlorella vulgaris microalgae with the photocatalytic properties of TiO2 NPs in order to investigate unexplored synergistic effects that could push the algal remediation technology toward a more promising cost-effective balance. We exploited non-living C. vulgaris, which keeps the biosorption properties of the living microalgae, but greatly enhancing the overall processability.C. vulgaris biomass was coupled with TiO2 NPs and the nanosols were then dried by means of a spray freeze drying (SFD) process able to produce highly reactive granules. A widespread physicochemical characterization supported the preparation and the performance evaluation, so highlighting the key-role of C. vulgaris/TiO2 interaction at the colloidal state.Heavy metal adsorption, tested for copper ions, and photocatalytic activity, assessed for Rhodamine B (RhB) photodegradation, were evaluated as key performances. The results pointed out a positive synergistic effect for hybrid samples consistent with the enhancement of metal biosorption which ranges from 103 mg g−1, for pristine C. vulgaris, to about 4000 mg g−1, when the biomass was coupled with the inorganic nanophase. The photocatalytic activity was well preserved with a complete RhB conversion after 1 h and even advanced in presence of SiO2NPs into the inorganic counterpart, so increasing the kinetic constant from 8.70 to 10.7 10−2 min−1. The results pave the way for the integration of these sorbent/photocatalytic hybrid materials into water remediation systems in an innovative sustainable design perspective.

Characterization of an exopolysaccharide produced by Enterobacter sp. YU16-RN5 and its potential to alleviate cadmium induced cytotoxicity in vitro.

Natural biopolymers have gained remarkable attention for bioremediation particularly in heavy metal removal and oil degradation due to their non-toxic nature and lack of secondary pollution. The exopolysaccharides (EPS) produced by the bacteria have become an important class of biopolymers that are employed in bioremediation. The bacteria isolated from the rhizospheric soil have higher metal tolerance and their EPS are effective in biosorption of heavy metals. Here, we report the characterization of an EPS (EPS-RN5) isolated from the root nodule-associated bacteria, Enterobacter cancerogenus strain YU16-RN5 and its heavy metal biosorption abilities. The bacteria isolated from the West coast of India was cultured in yeast extract mannitol (YEM) medium for EPS extraction and to study the production kinetics on a temporal scale. The biochemical composition, rheological properties and thermostability of EPS-RN5 was characterized by standard methods. The biosorption potential of EPS-RN5 against the selected heavy metals was analyzed by employing the inductively coupled plasma atomic emission spectroscopy (ICP-AES) technique. Further, cell culture experiments were used to test the role of EPS-RN5 in reducing the cytotoxicity exerted by the heavy metals in vitro using a human embryonic kidney cell line (HEK 293T). The bacteria showed good growth in YEM media and the maximum EPS yield was 1800mg/L at 96h. The molecular weight of EPS-RN5 was 0.7 × 106Da and it contained 61.5% total sugars and 14.5% proteins. The monosaccharide composition of the EPS included glucose, sorbose and galactose in the ratio 0.25:0.07:1.0. The EPS-RN5 showed high thermal stability with a degradation temperature of 273°C. Rheological analysis revealed the non-Newtonian behavior, with pseudoplastic characteristics. The EPS-RN5 efficiently absorbed cadmium and other heavy metals such as mercury, strontium, copper, arsenic, and uranium. In vitro studies revealed significant protective effect against the cadmium-induced cytotoxicity in HEK 293T cells. These results indicate the potential applications of EPS-RN5.

Biosorption of nickel, cobalt, zinc and copper ions by Serratia marcescens strain 16 in mono and multimetallic systems

The metallurgical industry is one of the main sources of heavy metal pollution, which represents a severe threat to life. Metals can be removed from aqueous solutions by using microbial biomasses. This paper analyses the heavy metal biosorption capacity of Serratia marcescens strain 16 in single and multimetallic systems. The results obtained show that Co(II), Ni(II) and Zn(II) biosorption in monometallic systems is two to three times higher than in the presence of bi-metallic and multimetallic solutions. Fourier transform infrared spectroscopy confirmed that carbonyl, carboxyl and hydroxyl were the main functional groups, as well as the amide bands I and II involved in metal uptake, which are present in external structures of the bacterial cell. The results obtained demonstrated the viability of S. marcescens strain 16 as a biosorbent for the design of eco-friendly technologies for the treatment of waste liquor.

Physicochemical and molecular characterization of heavy metal–tolerant bacteria isolated from soil of mining sites in Nigeria

BackgroundMining for precious metals is detrimental to the composition of soil structure and microbial diversity distribution and is a health risk to human communities around the affected communities. This study was aimed at determining the physical and chemical characteristics and diversity of bacteria in the soil of local mining sites for biosorption of heavy metals. ResultsResults of physical and chemical characteristics showed mean pH values and percentage organic carbon to range from 7.1 to 8.2 and 0.18 to 1.12% respectively with statistical significance between sampling sites (P ≤ 0.05). Similarly, cation exchange capacity, electrical conductivity, moisture, total nitrogen, and carbon/nitrogen ratio (C:N) in the soil ranged between 1.52 to 3.57 cmol/kg, 0.15 to 0.32 ds/m, 0.14 to 0.82%, 0.10 to 0.28%, and 1.7 to 4.8 respectively. The highest heavy metal concentration of 59.01 ppm was recorded in soils obtained from site 3. The enumeration of viable aerobic bacteria recorded the highest mean count of 4.5 × 106 cfu/g observed at site 2 with statistical significance (P ≤ 0.05) between the sampled soils. Alcaligenes faecalis strain UBI, Aeromonas sp. strain UBI, Aeromonas sobria, and Leptothrix ginsengisoli that make up 11.2% of total identified bacteria were able to grow in higher amended concentrations of heavy metals. The evolutionary relationship showed the four heavy metal–tolerant bacteria identified belonged to the phylum Proteobacteria of class Betaproteobacteria in the order Burkholderiales. Heavy metal biosorption by the bacteria showed Alcaligenes faecalis strain UBI having the highest uptake capacity of 73.5% for Cu. ConclusionIn conclusion, Alcaligenes faecalis strain UBI (MT107249) and Aeromonas sp. strain UBI (MT126242) identified in this study showed promising capability to withstand heavy metals and are good candidates in genetic modification for bioremediation.

A critical review of biosorption of dyes, heavy metals and metalloids from wastewater as an efficient and green process

Wastewater contains many organic and inorganic pollutants and discharging them into received waters leads to serious environmental problems. The wastewater that is produced from various industries contains a noticeable amount of dyes; heavy metals and metalloids this has remained one of the major environmental problems facing public health. Unfortunately, the conventional wastewater remediation process is unable to remove dyes and heavy metals completely. One of the widely used water treatment technologies is biosorption, biosorbents are considered to be an emerging green, cost-effective, and efficient alternative. Therefore, the search for locally or regionally available biomasses for heavy metals/metalloids and dyes removal gained rapid attention. Methylene blue, Crystal violet, Reactive black 5, and Congo red; Cd, Cr, Cu, Pb, Hg, Ni, and Zn; and As were selected as examples for dyes, heavy metals, and metalloids, respectively, In this regard, a comprehensive understanding of the biosorption capability of different biosorbents is necessary to know how they can remove inorganic and organic contaminants in wastewater. Biosorption is an ion exchange, complexation, and coordination process. Besides, the recent advances in various biomaterials-based biosorbents and different approaches of pollutants removal from wastewater with several examples to provide a backdrop for future research have been reviewed. This can be beneficial for developing more effective technologies to eliminate contaminants, thus bridging the gap between laboratory results and industrial use. crustacean shells, algae, chitosan are the most effective biosorbents. These biosorbents can serve as good alternatives to synthetic materials for pollutants removal from wastewater. • Biosorption is an emerging green, cost-effective, and efficient alternative Technology. • Biosorbents more beneficial for developing more effective technologies to eliminate contaminants. • Biosorption is ion exchange, complexation, and coordination process. • The availability of the biosorbents can bridge the gap between laboratory results and industrial use.

Biosorption of Cadmium by fungi isolated from Bharalu river, Assam

Heavy metal pollution in the aquatic ecosystem poses a serious threat to the human health and aquatic biodiversity around. There is urgent need to remediate heavy metals contaminated wastewater through eco friendly ways. Fungi and other microorganisms have been reported to have promising potential to remove heavy metals from wastewater through biosorption. Thus the present work aimed to isolate tolerant fungal species from different sites of a polluted river Bharalu in Assam. After preliminary screening, out of a total of 15 fungal isolates obtained, 4 isolates Aspergillus niger, Aspergillus flavus, Aspergillus fumigates and Colletotrichum gloeosporioides were selected for further study. Tolerance limit of the isolates for Cadmium (Cd) was carried out at concentrations ranging from 100 ppm to 1000 ppm. Results showed that the maximum tolerance was observed in Colletotrichum gloeosporioides (approx. 8.8 mm), followed by Aspergillus flavus (approx. 5.8 mm) at 400ppm. The biosorption efficiency at 400ppm revealed that the maximum Cd concentration was absorbed by fungal biomass of Colletotrichum gloeosporioides (12.83 mg/g) and the minimum by Aspergillus niger (3.91 mg/g). Molecular identification was carried out followed by PCR amplification of the fungal biomass showing highest absorption. The sequence obtained was submitted in the GenBank using BANkIt with accession number-MN714368 which showed high similarities with Colletotrichum gloeosporioides. This results indicated that fungus are promising and potential sources for metal biosorption and detoxification.

Biosorption of rare-earth and toxic metals from aqueous medium using different alternative biosorbents: evaluation of metallic affinity.

Currently, the world faces difficulties related to the quantity and quality of water because of industrial expansion, population growth, and urbanization intensification. Biosorption is considered a promising technology that can be applied to remove toxic metals (TMs) and rare-earth metals (REMs) in wastewater at low concentrations, due to its efficiency and low cost. In this work, we investigated different non-conventional biosorbents to remove metallic ions (TMs and REMs) in biosorptive affinity tests. Metallic affinity assays among lanthanum and different biosorbents showed that greater affinities were found for sericin-alginate beads crosslinked with polyvinyl alcohol (SAPVA) (0.280 mmol/g) and polyethylene glycol diglycidyl ether (SAPEG) (0.277 mmol/g), expanded vermiculite (0.281 mmol/g), Sargassum filipendula seaweed (0.287 mmol/g), and seaweed biomass waste (0.289 mmol/g). Among the biosorbents evaluated, SAPVA and SAPEG beads, besides to sericin-alginate beads crosslinked with proanthocyanidins (SAPAs) were selected for affinity assays with other REMs and TMs. Compared to other particles, SAPVA beads showed higher potential for biosorption by REMs with the following order of affinity: Yb3+ > Dy3+ > Nd3+ > Ce3+ > La3+. Additionally, the biosorptive affinity of TMs by SAPVA beads followed the order: Al3+ > Cr3+ > Pb2+ > Cu2+ > Cd2+ > Zn2+ > Ni2+.

Removal of Heavy Metals (Cd2+, Cu2+, Ni2+, Pb2+) from Aqueous Solution Using Hizikia fusiformis as an Algae-Based Bioadsorbent

This study investigated the applicability of algae (Hizikia fusiformis, Green gracilaria, and Codium fragile) for removing heavy metals (Cd2+, Cu2+, Ni2+, and Pb2+) from aqueous solutions. Among the algae, H. fusiformis was chosen as a bioadsorbent and modified with NaOH and HCl. The results showed that the biosorption capacity of H. fusiformis improved significantly after treatment with NaOH; however, H. fusiformis modified with HCl did not achieve the expected value. The NaOH treatment enhanced the biosorption of metals on the treated H. fusiformis because of the hydrolysis reaction producing carboxylic (–COOH) and hydroxyl groups (–OH). The kinetics for Cd2+, Cu2+, Ni2+, and Pb2+ biosorption well fitted to pseudo-first-order, pseudo-second-order, and Elovich models, with R2 of >0.994. The Freundlich model provided a good fit for the equilibrium biosorption of Cd2+, Cu2+, and Ni2+ by both algae and the Langmuir model for Pb2+. The maximum biosorption of metals was in the order Pb2+ >> Cu2+ ≈ Ni2+ > Cd2+, with qmax of 167.73, 45.09, 44.38, and 42.08 mg/g, respectively. With an increase in the solution pH, metal biosorption was enhanced, and considerable enhancement was observed in the pH range of 2–4. Thus, H. fusiformis is expected to be considered a superior candidate for metal biosorption.

Metal biosorption by magnetotactic bacteria isolated from fresh water sediments and characterization of extracted magnetosomes.

The focus of the present study is to isolate and identify magnetotactic bacteria from fresh water sediments in Salem region, Tamil Nadu. Fresh water sediments were collected and characterized by X-ray diffraction to detect the crystalline nature of particles. Totally 12 isolates were screened for the metal biosorption efficiency in modified nutrient agar plates with 10mg (lower concentration) of four different metals viz., manganese chloride, zinc sulphate, copper sulphate and potassium dichromate. Followed by testing their ability to tolerate higher concentration of metals viz., 20mg, 30mg, 50mg, 70mg, 90mg and 150mg/50ml was analyzed. Only four bacteria survived the highest concentration of manganese and zinc (3000µg/ml), CuSO4 and K2Cr2O7 at a concentration of 1400µg/ml and 1800µg/ml, respectively. The four bacterial strains Stenotrophomonas maltophilia, two Pseudomonas aeruginosa strains and Achromobacter xylosoxidans were grown in modified nutrient broth (NB) and Luria Bertani (LB) incorporated with metals such as manganese, zinc, copper and chromium and tested for their efficacy to sustain metal stress. Since the two bacterial strains (SBY and KY1) were able to grow in both medium with a potential to with stand higher metal concentration these strains were further studied. A metal tolerant magnetotactic bacterial strain Pseudomonas aeruginosa SBY was confirmed by TEM analysis to detect the accumulated metal within the cell. As bacterial strains were capable of tolerating higher concentration of metal, they may have avital role in environmental bioremediation.

Removal of Manganese and Copper from Aqueous Solution by Yeast Papiliotrema huenov

Papiliotrema huenov was previously reported to be highly tolerant of a range of extremely toxic heavy metals. This study aimed to identify the potential of P. huenov to remove manganese and copper from aqueous solution. Physical conditions which affect removal of Mn(II) and Cu(II) were determined. Optimal temperature for adsorption of both metal ions was 30 °C, and optimal pH for maximum uptake of Mn(II) and Cu(II) were 5 and 6, respectively. Under these conditions, living cells of P. huenov accumulated up to 75.58% of 110 mg/L Mn(II) and 70.5% of 128 mg/L Cu(II) over 120 h, whereas, the removal efficiency of metal ions by dead cells over 1 h was 60.3% and 56.5%, respectively. These results indicate that living cells are more effective than dead biomass for bioremediation, but that greater time is required. The experimental data extends the potential use of P. huenov in biosorption and bioaccumulation of toxic heavy metals to copper and manganese, two of the most common industrial contaminants.

A new soil microcosm to evaluate the Cd, Cu and Pb biosorption by Absidia cylindrospora

Fungi could be considered as an effective tool for treating metal pollution in soils because of their metal tolerance and biosorption capacity. While most of biosorption studies intended for bioremediation trials are carried out in liquid medium, this study presents the development of a new type of soil microcosm, designed to evaluate the fungal biosorption of metals in a solid medium. The research focused on the bioaugmentation with the fungus Absidia cylindrospora of a soil artificially contaminated by metals (Cd, Cu, and Pb). Soil microcosms were performed in layers, and a separation technique including a centrifugation step was developed. The results showed that the centrifugation step does not cause the leaching of metals from the soil. The developed procedure allows to effectively separate the mycelium from the soil at the end of the experiment. It leads to an accurate evaluation of the metal accumulated by the fungus, by better estimating the bioaccumulation factor (BAF) which was superior to 1 for the metals studied. In addition, Absidia cylindrospora was viable after 30 days experiment, and able to biosorb considerable amounts of the metals studied from the contaminated soil; it accumulates 171 mg.kg−1 of Cu, 146 mg.kg−1 of Cd and 119 mg.kg−1 of Pb. These results confirm the ability of the fungal strain to be used for bioremediation studies.

Optimization and Simulation of Process Parameters in Biosorption of Heavy Metals by Alcaligenes faecalis Strain UBI (MT107249) Isolated from Soil of Local Mining Area in North-West Nigeria

ABSTRACT The use of biological molecules to control pollutants, especially heavy metals that pollute our atmosphere, is gaining traction. In this study, simulation and optimization of process parameters using one-factor-at-a-time and response surface methodology (RSM) were employed to assess conditions for heavy metal tolerant bacteria isolated from local mining area employed in biosorption of heavy metals. Morphological, biochemical, and molecular characteristics of the isolate was determined using standard procedures. The agar plate method was used to determine heavy metal tolerance of the bacterial isolate. The effect of factors affecting biosorption of heavy metals was assessed using one-factor-at-a-time and response surface methodology respectively. The Gram-negative Alcaligenes faecalis strain UBI isolated in this study was capable of tolerating 27.0ppm of Pb2+. Optimum temperature and pH recorded were 35°C and 5 respectively. Similarly, optimum metal concentration indicated 2.5ppm with 12 hours contact time and at 7% of Inocula size (v/v) respectively. Simulation by RSM showed that the model is significant (p = .0013). The statistical accuracy of the model was elaborated by the non-significant lack of fit. The R2 (0.98) value highlights a perfect model likewise the low value of the coefficient of variance (CV = 3.09%). This study supports the idea of using bacteria as a panacea to heavy metal pollution under-regulated process parameters.

Biosorption of Chromium from Textile Wastewater Using Mimosa pudica Tannin Gel

<p>The heavy metal content is very dangerous because it can pollute the environment. One of the heavy metals waste commonly found in the textile industry is chromium (Cr). <em>Mimosa pudica</em> is a weed plant and its availability is very abundant. However, it also contains tannin which can be developed into tannin gel biosorbent to adsorption heavy metal content in the wastewater. The purpose of this research is to study <em>Mimosa pudica</em> tannin as a Cr biosorbent from textile wastewater. There are two steps to synthesis tannin gel biosorbent. They are the tannin extraction and the condensation polymerization process. Tannin is easily soluble in water so the condensation polymerization process is needed to make it insoluble in water. The extraction of <em>Mimosa pudica </em>tannin was done using water solvent. The condensation polymerization process was done by the reaction of tannin extract and formaldehyde. The Cr content of textile industry wastewater in the Pasar Kliwon, Surakarta was 4 ppm. The results of the biosorption of Cr heavy metal using <em>Mimosa pudica</em> tannin gel showed that the remaining Cr heavy metal was 0.7098 ppm. It was already below the threshold which was 1 ppm.</p><p> </p><p><strong>Keywords:</strong> biosorption, condensation polymerization, extraction, <em>Mimosa pudica</em>, tannin gel</p>

Application of radiotracer technique in remediation of Zn(II) from aqueous solutions by dry cowdung powder

Heavy metal pollution is caused due to anthropogenic activities and is considered as a serious environmental problem which endangers human health and environment. The present study deals with biosorption, an eco-friendly technique for the removal of heavy metal Zn(II) from aqueous medium. Various natural materials have been explored for the uptake of metal ions, where most of them are physically or chemically enhanced. Dry cowdung powder (DCP) has been utilized as a low-cost, environmentally friendly humiresin without any pre-treatment, thus demonstrating the concept of Green Chemistry. Batch biosorption studies using 65Zn(II) tracer were performed and the impact of different experimental parameters was studied. Results revealed that at pH 6, 94 ± 2% of Zn(II) was effectively biosorbed in 5 min, at 303 K. The process was spontaneous and exothermic, following pseudo-second-order reaction. The mechanism of heavy metal biosorption employing green adsorbent was therefore elucidated in order to determine the optimal method for removing Zn(II) ions. DCP has a lot of potential in the wastewater treatment industry, as seen by its ability to meet 3A's affordability, adaptability, and acceptability criteria. As a result, DCP emerges as one of the most promising challengers for green chemistry and the zero-waste idea.

Poly(ethylene terephthalate) waste recycling and uses for enhancement of bioremediation of arsenic in groundwater

Various studies on arsenic pollution reveal that high concentrations of arsenic were found in many districts of western Uttar Pradesh, India. There arsenic concentrations were higher than the permissible limit given by the World Health Organization (WHO) and Bureau of Indian Standards (BIS). There is a requirement to bioremediate arsenic due to its harmful effect. On the other hand, Poly(ethylene terephthalate) was being repeatedly used as packaging materials, due to which various environmental issues regarding PET waste disposal have generated. In the present study, PET waste was recycled into various aromatic amides by aminolysis and ammonolysis. These aromatic amides were used as surfactants. Various studies have been carried out for biosorption of heavy metal through Bacillus cereus. The efforts were made to enhance bioremediation of arsenic in different water samples spiked with Bacillus cereus in the presence of synthesized aromatic amides. This study explored the possibility to increase bioremediation of arsenic by bacteria using recycled PET waste. The results of this study indicated that in the presence of aromatic amides the percent biosorption could be enhanced by bacteria up to 20–60%.The other significant approach of this study is recycling of PET waste.

Biomass of the macrophyte remedies and detoxifies Cd(II) and Pb(II) in aqueous solution.

Aquatic plants are considered to be important remedial agents in aquatic environments contaminated by metals. The Salvinia biloba macrophyte was evaluated in relation to its removal kinetics, adsorption capacity, and toxicology, aiming at its application in the removal of Cd+2 and Pb+2 ions from aqueous solutions. A batch-type system was used, in which the plants were cultivated in microcosms containing nutritive solution and metallic ions, stored in a controlled environment (pH, temperature, and luminosity). The removal kinetics consisted in the analysis of efficiency, varying the concentrations of the metals, and time of cultivation of plants in solution. To describe the process, adsorption isotherms were constructed with the equilibrium data, which were later adjusted to Langmuir and Freundlich models. The toxicological trial was performed by sub-acute exposure test of Caenorhabditis elegans nematode to phytoremediated solutions. The results highlight the remedial effect of the plant in solutions contaminated with both metals. The kinetic study demonstrated that the plant responds differently to metals, and physical-chemical and biological processes can be attributed to the removal of metals from the solution by the plant. The equilibrium time obtained was 48 h for both metals, and the adsorption capacity was higher for Cd2+. The toxicological evaluation indicates that there was a reduction in toxicity after the remediation of the solutions by S. biloba, for all times and concentrations evaluated. Salvinia biloba was efficient for the removal of Cd2+ and Pb2+ metals from aqueous solution. The plant is a low-cost metal biosorbent and can be considered promising for phytoremediation strategies in liquid effluents and water bodies.

Heavy metal biosorption by Extracellular Polymeric Substances (EPS) recovered from anammox granular sludge

The recovery and conversion of Extracellular Polymeric Substances (EPS) from sewage sludge into bio-based commodities might improve the economics and environmental sustainability of wastewater treatment. This contribution explores the application of EPS from anammox granular waste sludge as biosorbent for the removal of heavy metals, specifically lead, copper, nickel, and zinc. Adsorption capacities equivalent or higher than well-established adsorbent media emerged from single-metal biosorption studies (up to 84.9, 52.8, 21.7 and 7.4 mg/gTSEPS for Pb2+, Cu2+, Ni2+ and Zn2+, respectively). Combining spectroscopic techniques, a mechanistic hypothesis for metal biosorption, based on a combination of electrostatic interaction, ion exchange, complexation, and precipitation, was proposed. The adsorption mechanisms of extracted EPS and non-extracted EPS in the native biomass were indirectly compared by means of single-metal biosorption studies performed with pristine granules (adsorbing up to 103.7, 36.1, 48.2 and 49.8 mg/gTSgranules of Pb2+, Cu2+, Ni2+, and Zn2+, respectively). In comparison with pristine anammox granules, EPS showed lower adsorption capacities except for copper and different adsorption pathways as postulated based on the adsorption data interpretation via theoretical models. The multi-metal biosorption tests excluded significant competitions among different heavy metals for the EPS binding sites, thus opening further scenarios for the treatment of complex wastewaters.