Sorption Of Heavy Metals Research Articles

Coffee Husk and Lignin Revalorization: Modification with Ag Nanoparticles for Heavy Metals Removal and Antifungal Assays

This study presents the use of the modified coffee husk and coffee lignin as sorbents in the heavy metal ions sorption of Pb(II), Cd(II), Cr(III), and Cu(II) in an aqueous solution. The modification of sorbents was carried out by the impregnation method, using silver nitrate (AgNO3) and sodium borohydride (NaBH4) as a nanoparticles’ (NPs) precursor, and reducing agent, respectively. The obtained nanocomposite material was morphologically characterized by electron microscopy. In addition, an evaluation of metal ions’ sorption, pseudo-first-order, and pseudo-second-order kinetics modeling was performed. Finally, antifungal activity was evaluated on different Candida species. Coffee and lignin modified with AgNPs increased the extraction capacity with the highest sorption for Pb ions with 2.56 mg/g and 1.44 mg/g, respectively.

Modified low cost engineered biochar prepared from neem de-oiled cake for heavy metal sorption

In this work, the sorption of nickel, chromium, and copper metal ions from an aqueous solution was tested using low-cost engineered neem de-oiled cake biochar (ENDCB). The characterization of ENDCB was performed by BET and SEM techniques. The potential parameters effects such as adsorbent dosage (1–5 g/L), temperature (25–60 °C), contact time (15–120 min), and metal ion concentration (25–150 mg/L) of copper, chromium, and nickel were performed on the batch mode. The greater removal percentageof copper, nickel, and chromium was noticed at a contact time of 60 min, initial concentration of 100 mg/L, the adsorbent dosage of 5 g/l, and temperature of 30 °C as 93.3%, 85.4%, and 96.6% respectively. Among various regenerating agents, maximum desorption percentage (92.3% copper, 84.23% nickel, and 95.5% chromium) was noticed at 0.8 M H2SO4.The ENDCB showed stability up to 3 cycles.

Sawdust as Low-Cost Adsorbents for the Removal of Heavy Metals From Water

Sawdust is currently investigated as a sorbent to eliminate heavy metals from wastewater and other aqueous solutions. The raw material is relatively cheap and is available in abundance. Sawdust also helps to eradicate other contaminants, such as dyes, pesticides, phenols, toxic salts, etc. This literature discusses the elimination of heavy metals from wastewater through the help of sawdust. The composition of the sawdust, and the work done concerning the sorption of heavy metals, kinetics, adsorption isotherm, etc., are discussed in this study. The adsorption capacity of sawdust depends on the concentration of adsorbate, composition and characterisation of adsorbent, and the type of modifications. Also, the challenges faced during research are mentioned in this literature. More research should be done in this field to enhance the use of sawdust on large-scale cost-effectively.

Detection and Sorption of Heavy Metal Ions in Aqueous Media by a Fluorescent Zr(IV) Metal-Organic Framework Functionalized with 2-Picolylamine Receptor Groups.

Increasing global environmental pollution due to heavy metal ions raises the importance of research on new multifunctional materials for simultaneous detection and removal of these contaminants from water resources. In this study, we report a microporous 8-connected Zr4+ metal-organic framework (MOF) based on a terephthalate ligand decorated with a chelating 2-picolylamine side group (dMOR-2), which shows highly efficient fluorescence sensing and sorption of heavy metal cations. We demonstrate by detailed fluorescence studies the ability of a water-dispersible composite of dMOR-2 with polyvinylpyrrolidone for real-time detection of Cu2+, Pb2+, and Hg2+ in aqueous media. The limits of detection were found to be below 2 ppb for these species, while the system's performance is not affected by the presence of other potentially competitive ions. In addition, sorption studies showed that a composite of dMOR-2 with calcium alginate (dMOR-2@CaA) is an excellent sorbent for Pb2+ and Cu2+ ions with capacities of 376 ± 15 and 117 ± 4 mg per gram of dMOR-2@CaA, respectively, while displaying the capability for simultaneous removal of various heavy metal ions in low initial concentrations and in the presence of large excesses of other cationic species. Structural and spectroscopic studies with model ligands analogous to our material's receptor unit showed chelation to the 2-picolylamine moiety to be the main binding mode of metal ions to dMOR-2. Overall, dMOR-2 is shown to represent a rare example of a MOF, which combines sensitive fluorescence detection and high sorption capacity for heavy metal ions.

Nickel ion extracellular uptake by the phototrophic bacterium Rhodobacter sphaeroides: new insights from Langmuir modelling and X-ray photoelectron spectroscopic analysis

The presence of anionic functional groups on the surface of microbial cells makes the bacterial biomass very attractive as metal cation removal tool for environmental bioremediation. To go insight to the heavy metal sorption abilities of Gram-negative bacteria, we characterized the extracellular uptake of Ni2+ ions by the phototrophic bacterium Rhodobacter sphaeroides, whose ability to sequester toxic metal ions has been widely documented. The sorption process proved to be well described by the Langmuir model, suggesting that the cell envelope behaves as an ideal adsorbent surface, showing a layer of chemically equivalent binding sites with high affinity for Ni2+. X-ray photoelectron spectroscopic data reveal that, at binding site saturation, Ni2+ ions fully displace alkali metal ions from the bacterial surface, while they are unable to displace Ca2+ and Mg2+ from their tight binding sites. The analysis of carbon, nitrogen and oxygen speciation, as arisen from high resolution spectra fitting, highlights that the Ni2+/K+ cation exchange affects the surface distribution of main chemical components, with increased contribution by peptides and phosphatidylcholines. A role of Ni2+ ions in favoring the stacking and/or packing of lipopolysaccharide sugar chains by interaction with carboxylate groups is proposed and discussed.

Use of superabsorbent polymer in soil-cement subsurface barriers for enhanced heavy metal sorption and self-healing

Conventional subsurface barrier materials for contamination containment deteriorate in aggressive environments and only have a limited exchange/adsorption capacity for heavy metals. This study focused on the potential use of superabsorbent polymer (SAP) in soil-cement subsurface barriers for enhanced heavy metal sorption and self-healing. The SAP adsorption results for lead, copper, zinc and nickel were well fitted by the Langmuir model. The SAP had the highest adsorption capacity for lead at 175 mg/g, and plays a key role in the removal of the heavy metals in an acidic environment. In addition, the incorporation of SAP in soil-cement increased the ductility and had negligible adverse effects on mechanical and permeability properties. When cracks propagate in the matrix, the SAP is exposed to the ingress of water and swells, and this swelling reaction seals the cracks. The SAP-containing soil-cement demonstrated enhanced self-healing performance in terms of the recovery of permeability. The uniform dispersion and the 3D network of the SAP were observed using micro-CT scanning, and good bonding and self-healing mechanism were confirmed by SEM-EDX analysis. The results suggest the significant potential for the SAP-based approach for the development of more resilient subsurface barriers with enhanced heavy metal sorption and self-healing.

Portable SA/CMC entrapped bimetallic magnetic fly ash zeolite spheres for heavy metals contaminated industrial effluents treatment via batch and column studies

Heavy metals are perceived as a significant environmental concern because of their toxic effect, bioaccumulation, and persistence. In this work, a novel sodium alginate (SA) and carboxymethylcellulose (CMC) entrapped with fly ash derived zeolite stabilized nano zero-valent iron and nickel (ZFN) (SA/CMC-ZFN), followed by crosslinking with CaCl2, is synthesized and applied for remediation of Cu(II) and Cr(VI) from industrial effluent. The characterization of the adsorbent and its surface mechanism for removing metals were investigated using advanced instrumental techniques, including XRD, FT-IR, SEM–EDX, BET, and XPS. The outcomes from the batch experiments indicated that monolayer adsorption on homogeneous surfaces (Langmuir isotherm model) was the rate-limiting step in both heavy metals sorption processes. The maximum adsorption capacity of as-prepared SA/CMC-ZFN was 63.29 and 10.15 mg/g for Cu(II) and Cr(VI), respectively. Owing to the fact that the wastewater released from industries are large and continuous, a continuous column is installed for simultaneous removal of heavy metal ions from real industrial wastewater. The outcomes revealed the potential of SA/CMC-ZFN as an efficient adsorbent. The experimental breakthrough curves fitted well with the theoretical values of Thomas and Yoon-Nelson models. Overall, the results indicated that SA/CMC-ZFN is a viable, efficient, and cost-effective water treatment both interms of batch and column processes.

Sorption of Heavy-Metal Ions from Aqueous Solutions by Mesoporous Nickel 2-Ethylimidazolate

Sorption of Heavy-Metal Ions from Aqueous Solutions by Mesoporous Nickel 2-Ethylimidazolate

A deep learning neural network approach for predicting the factors influencing heavy-metal adsorption by clay minerals

AbstractThe treatment of water containing heavy metals has attracted increasing attention because the ingestion of such water poses risks to human health. Due to their relatively large specific surface areas and surface charges, clay minerals play a significant role in the adsorption of heavy metals in water. However, the major factors that influence the adsorption rates of clay minerals are not well understood, and thus methods to predict the sorption of heavy metals by clay minerals are lacking. A method that can identify the most appropriate clay minerals for removal of a given heavy metal, based on the predicted sorption of the clay minerals, is required. This paper presents a widely applicable deep learning neural network approach that yielded excellent predictions of the influence of the sorption ratio on the adsorption of heavy metals by clay minerals. The neural network model was based on datasets of heavy-metal parameters that are available generally. It yielded highly accurate predictions of the adsorption rate based on training data from the dataset and was able to account for a wide range of input parameters. A Pearson sensitivity analysis was used to determine the contributions of individual input parameters to the adsorption rates predicted by the neural network. This newly developed method can predict the major factors influencing heavy-metal adsorption rates. The model described here could be applied in a wide range of scenarios.

Three dimensional hydrogel evaporator made of nano level antireflection particles for high-efficiency solar steam generation

Solar-driven interface evaporation technology provides a sustainable green method for the acquisition of freshwater resources. In this article, a hydrogel of a three-dimensional porous structure has been synthesized for solar steam generation. Ag nanoparticles are used as a photothermal material. Given the long-term utilization of Ag nanoparticles, they have been coated with a SiO2 layer. Moreover, SiO2 can act as a “reduced reflection” layer that can minimize light reflection on a single Ag nanoparticle, and enhance the nanoparticles’ absorbing ability of optical waves. Furthermore, the performance of the evaporator is significantly improved by the addition of cuttlefish powder material in the hydrogel. Specifically, under 1 KW m−2, the surface temperature of the evaporator reached 41 ℃, the steam generation rate was 1.78 (kg m−2h−1), and the solar thermal conversion efficiency is 94 %. Moreover, when the evaporator is used in heavy metal sorption, the resulting evaporated water meets international drinking water criteria. After photothermal evaporation, the ion concentrations of Cu, Mn and Cd decreased from 1000, 100 and 20 mg L−1 to 0.021, 0.017 and 0.04 mg L−1 respectively. This study provides a feasible idea for the practical application of photothermal evaporator.

Physical and chemical properties of soils in Kharkiv (Ukraine).

The purpose of this work is to determine the physical and chemical properties of soils in different regions of Kharkiv (Ukraine) and to explore their impact on the sorption of heavy metal ions: Cu2+ and Zn2+. It has been established that the soils of gleyic chernozem and typical heavy black earth by their characteristics belong to highly buffer humified soils. According to the increase in the sorption capacity of the soil, it can be arranged in the following row: haplic arenosol < mollic gleyic fluvisol < gleyic chernozem < typical heavy black earth. The index of saturation with cations for typical heavy black earth is an order of magnitude higher than for the other studied soils. The distribution of mobile forms of copper and zinc in soils is determined by their type. The absorption capacity of the studied soils in relation to Cu2+ and Zn2+ directly correlates with a decrease in the pH of the soil solution, with the content of humus and with an increase in the carbon ratio of humic and fulvic acids. The materials of the research can be used to control the ecological situation in the city.

A Facile Review on the Sorption of Heavy Metals and Dyes Using Bionanocomposites

Presently, hazardous metal and dye removal from wastewater is one of the major areas of research focus. For the elimination of these contaminants, many approaches have been devised and applied. However, the accomplishment of various water treatment processes has largely depended on the medium utilized and the associated problem with the leaching of harmful compounds into the water process with most commercial and chemically manufactured materials for water treatment processes. Hence, this study is aimed at reviewing existing studies on the sorption of heavy metals (HMs) and dyes using bionanocomposites (BNCs). The key focus of this review is on the development of eco-friendly, effective, and appropriate nanoadsorbents that could accomplish superior and enhanced contaminant sequestration using BNCs owing to their biodegradability, biocompatible, environmentally friendly, and not posing as secondary waste to the environment. The sorption of most pollutants was observed to be pH, sorbent dosage, and initial contaminant concentration-dependent, with most contaminants’ elimination taking place in the pH range of 2-10. The sorption process of HMs and dyes to various BNCs was superlatively depicted utilizing the Langmuir (LNR) and Freundlich (FL) as well as the pseudo-second-order (PSO) models, suggestive of the sorption process of a monolayer and multilayer and the chemisorption process, the rate-limiting stage in surface sorption. The established sorption capacities for the reviewed sorption process for various contaminants ranged from 1.47 to 740.97 mg/g. Future prospective for the treatment and remediation of contaminated water using BNCs was also discussed.

UNSTEADY PROCESSES OF ION EXCHANGE SORPTION OF COPPER IONS IN A CONTINUOUS IDEAL MIXING APPARATUS

The article is devoted to the study of transient processes of ion-exchange sorption of heavy metal ions on a sulfonic acid cation exchanger in a vessel with a stirrer. A mathematical description of the ion exchange process is proposed, taking into account the following simplifying assumptions: at the initial moment of time, a solution and an ion exchanger containing heavy metal ions are inside the apparatus; the rate of ion exchange is limited by both internal and external diffusion; the process equilibrium is described by the Nikolsky adsorption isotherm equation; the structure of the movement of the solution and the ion exchanger in the apparatus is described by the ideal mixing model. In accordance with the accepted assumptions, a mathematical description of the process is formulated, including the equation of the material balance of the apparatus, the equation of the adsorption isotherm, the equation of diffusion kinetics, as well as the initial and boundary conditions of the third kind. The solution of the problem is carried out on an electronic computer by a numerical method, in which the characteristic equation of a continuous-action apparatus of complete mixing is used to find the unknown concentration of the solution. To test the adequacy of the developed model to the real process, experimental studies of transient processes of ion-exchange sorption of copper ions on the Lewatit S-100 sulfonic acid cation exchanger in a laboratory capacitive apparatus with a stirrer were carried out. During the research, acceleration curves were taken, on the basis of which the parameters of the non-stationary ion-exchange process were calculated: acceleration time, time constant, gain of the object and the maximum rate of change in the concentration of the solution at the outlet of the apparatus. Comparison of the results of calculation and experiment made it possible to conclude that the developed mathematical description is adequate to the real process. The discrepancy between the calculation and the experiment does not exceed 14%. Recommendations are given on the application of the obtained dependences for practical application.

Composite aerogels based on reduced graphene oxide decorated with iron oxide nanoparticles for the sorption of heavy and rare earth metals from multicomponent solutions

Composite aerogels based on reduced graphene oxide decorated with iron oxide nanoparticles for the sorption of heavy and rare earth metals from multicomponent solutions

Cadmium and lead adsorption and desorption by coffee waste-derived biochars

Biochar derived from coffee waste has been reported as a promising material for heavy metal sorption. However, if the intended use is environmental remediation, knowing the extent to which desorption may occur is critical. Thus, the objective of this work was to evaluate the efficiency of spent coffee ground (SCG) and coffee parchment (CP) biochars pyrolyzed at 700 °C under laboratory conditions, in the sorption of Cd and Pb from aqueous solutions, in a pH range from 2 to 10, and their retention after an induced desorption process with a 2.9 pH acetic acid solution. Both biochars were alkaline, and the initial pH of the solution had a large effect on the sorption capacity of SCG but a small effect on the sorption capacity of CP. The Pb sorption capacity was higher for CP (18.6 mg·g–1) than for SCG (11.4 mg·g–1), while both biochars had low Cd retention capacities (1.18 mg·g–1). Coffee parchment also showed the highest Pb retention (30% to 87%), while for Cd there was no difference between CP and SCG biochars. Our results showed that metal precipitation was the main mechanism for metal immobilization and CP biochar proved to be more reliable than SCG, mainly for Pb, due to its higher sorption capacity and lower metal release by desorption than SCG. These characteristics are particularly important for the use of biochar in environmental remediation. Besides that, the biochar production represents an eco-friendly destination for these feedstocks, contributing to the circular economy.

Effective removal of heavy metals in industrial wastewater with novel bioactive catalyst enabling hybrid approach

Recent years, heavy metal reduction of contaminated atmosphere using microbes is heightened worldwide. In this context, the current study was focused on heavy metal resistant actinomycete strains were screened from effluent mixed contaminated soil samples. Based on the phenotypic and molecular identification, the high metal resistant actinomycete strain was named as Nocardiopsis dassonvillei (MH900216). The highest bioflocculent and exopolysaccharide productions of Nocardiopsis dassonvillei (MH900216) was confirmed by various invitro experiments result. The heavy metal degrading substances was characterized and effectively confirmed by Fourier transform infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD), Scanning electron microscope (SEM). Further, the heavy metal sorption ability of actinomycete substances bioflocculent was exhibited 85.20%, 89.40%, 75.60%, and 51.40% against Cd, Cr, Pb and Hg respectively. Altogether, the bioflocculent produced actinomycete Nocardiopsis dassonvillei (MH900216) as an excellent biological source for heavy metal reduction in waste water, and it is an alternative method for effective removal of heavy metals towards sustainable environmental management.

Simultaneous sorption of heavy metals on Algerian Bentonite: mechanism study.

Industrialization has induced tremendous environmental problems, particularly surface and underground water pollution by harmful heavy metals. In this work, we attempt to eliminate simultaneously iron and cadmium from aqueous solutions by adsorption on Algerian Bentonite. This abundant material was used without any modification. The sorption mechanism was investigated, and effects of pH, initial adsorbate and adsorbent concentrations were studied. The kinetics study revealed that equilibrium was reached after 120 min for both metals, and maximal adsorbed quantities of cadmium (76 mg/g) and iron (55 mg/g ) were obtained at pH = 10 and 8 respectively. Different kinetic models were tested, such as pseudo first-order, pseudo second-order, film and intraparticle diffusion models. The pseudo second-order model fits well the experimental data. Biot number values (2-39) show that the simultaneous sorption process is controlled by film diffusion due to electrostatic interactions between negatively charged surface and cations, then by the internal diffusion and formation of bonds between cations and adsorbent constituents. Also, compared to iron, the high and rapid sorption of cadmium reflects the selective nature of the sorption process. These results show that raw bentonite could be used without further treatment as an efficient sorbent for heavy metal mixtures.

Influence of Pyrolysis Temperature on the Heavy Metal Sorption Capacity of Biochar from Poultry Manure.

Sorption properties of various biochars have been extensively investigated by many researchers. One of the parameters that have a significant impact on sorption properties is pyrolysis temperature. This paper presents a study on the effect of pyrolysis temperature (425, 575, 725 °C) on the sorption properties of poultry-manure-derived biochar (BPM). The produced biochars, i.e., BPM425, BPM575 and BPM725, demonstrated specific properties at 425, 525 and 752 °C such as high pH (10.40, 10.65 and 12.45), high ash contents (52.07, 61.74 and 78.38%) and relatively low BET (Brunauer, Emmett and Teller) surface area (11, 17 and 19 m2·g−1). The analysis of the mineral phases of the BPMs confirmed the buffering capacity. The investigated biochars were tested for sorption of Zn, Cd and Pb in mono-, double- and triple-metal batch sorption tests. According to the obtained results, biochar produced at a temperature of 575 °C (BPM575) can function as a sufficient sorbent for the removal of Zn, Cd and Pb from a water solution. The presented results do not confirm the effect of competing metal ions on the sorption efficiency of the selected metals by the investigated biochars. Based on that, the studied biochar sorbents can be used in environments contaminated with many metals.

Insights into the Simultaneous Sorption of Ciprofloxacin and Heavy Metals Using Functionalized Biochar

Biochar and chitosan are considered as green and cost-effective adsorbents for water purification; the combination of these two materials may lead to an improved adsorption capacity of the generated adsorbents. Most sorption studies have been focused on the ability to adsorb one contaminant or the same type of contaminants. Thus, this study aimed to produce chitosan-biochar beads (CH-BB) and test their efficiency in the simultaneous removal of a metal-complexing antibiotic, ciprofloxacin (CIP), and three metal(loid)s (As, Cd and Pb). Modification of raw pig manure biochar resulted in an increase in its adsorption capacity, except for Pb. The highest increment was observed for As (almost 6-fold) and the lowest was observed for CIP (1.1-fold). The adsorbent was able to simultaneously remove all targeted contaminants, individually and in the mixture. The adsorption capacity of CH-BB followed the order: Pb &gt; Cd &gt; &gt;As &gt; CIP. When Pb and As were present in the same mixture, their removal efficiency increased from 0.13 ± 0.01 to 0.26 ± 0.05 mg/g for As and from 0.75 ± 0.08 to 0.85 ± 0.02 mg/g for Pb due to their co-precipitation. The CIP–metal complexation probably resulted in a reduced adsorption ability for inorganics due to the decreased concentration of free ions. The presence of metals and metalloids led to alterations in CIP’s mobility.

Preparation and optimization of a low-cost adsorbent for heavy metal ions from red mud using fraction factorial design and Box-Behnken response methodology

Red mud (RM) is a solid waste generated from the alumina refining industry. The utilization of RM to prepare sorbent has attracted researchers’ attention. This study aimed to prepare a low-cost adsorbent for heavy metal ions by activating RM using Ca2+ and Mg2+ mixed solution neutralization and high-temperature treatment. Pb(Ⅱ) and Zn(Ⅱ) were selected as target contaminants to investigate the possibility of this adsorbent to remove heavy metal ions from the liquid. The Fractional Factorial Design and Box-Behnken design were used to screen the significant preparation parameters and obtain the optimum preparation conditions. The results demonstrated that neutralization time, calcination temperature, and calcination time were determined as significant factors affecting the adsorption capacity of Pb(Ⅱ) and Zn(Ⅱ), and the optimum preparation parameters were the solution concentration of 1.5 mol/L, the liquid-solid ratio of 40 ml/g, the neutralization time of 114 min, calcination temperature of 518 ℃, and the calcination time of 148 min. The physicochemical characterizations of neutralization-calcination RM (NCRM) were determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and N2 adsorption isotherm analysis. The results revealed that the main mineral phase of NCRM was hematite, calcite, and cancrinite, and NCRM had a loose structure and abundant pores, which contributes to the sorption of heavy metal ions. The adsorption kinetics study referred to satisfactory adsorption of Pb(Ⅱ) via pseudo-first-order model and pseudo-second-order model, while pseudo-second-order model was the best model to describe adsorption of Zn(Ⅱ) onto NCRM. Based on the batch experiment, the maximum adsorption capacities of Pb(Ⅱ) and Zn(Ⅱ) were 218.82 and75.58 mg/g, respectively. The excellent adsorption performance of NCRM on Pb(Ⅱ) and Zn(Ⅱ) implies that this material is a promising material for removing heavy metal ions from contaminated water.