Sorption Of Heavy Metals Research Articles

Sorption of Heavy Metals by Sewage Sludge and Its Mixtures with Soil from Wastewater Treatment Plants Operating in MBR and INR Technology.

Sewage sludge is a very complex system, with solids and water. It is generated as waste from wastewater treatment. Sewage sludge is used to fertilize agricultural and forest areas and to rehabilitate devastated areas. It is a good organic fertilizer because it contains significant amounts of nutrients beneficial for plant development and humus-forming substances. The composition of sludge from municipal wastewater treatment plants is similar to soil organic matter, therefore it can be used to improve the physicochemical properties of soil, increasing its sorption capacity. Research material was collected in the Swietokrzyskie and Mazowieckie Voivodships. Sewage sludge was collected from the wastewater treatment plants in Sitkowka Nowiny (Sitkowka) and Kunow, as well as high-quality agricultural soil from Opatowiec and sandy-clay soil from Jastrzebie. Research was carried out on the sorption of heavy metals (Cd, Cr, Cu, Pb, Ni, Zn) by mixtures of sewage sludge with soil. The calculations were made for the concentrations of heavy metals in sewage sludge, soil, and sewage sludge–soil mixtures. The geoaccumulation index (Igeo) and the risk assessment code (RAC) were calculated. Increased sorption capacity was demonstrated in samples with a predominance of sewage sludge. It was shown that heavy metals from sewage sludge, after mixing with soil, changed their form from immobile to mobile.

Structure and Potential Applications of Polyamide 6/Protein Electro-spun Nano-fibrous Mats in Sorption of Metal Ions and Dyes from Industrial Effluents

The main objective of this work is the preparation of nano-fibrous mats (NFM) from polyamide 6 (PA6) reinforced and functionalized by renewable proteinic waste and examining their potential use for the sorption of heavy metal ions and dyes from wastewater from textile plants. Two renewable waste biopolymers; namely keratin (from waste of wool combing) and sericin (from degumming of natural silk) were extracted and regenerated. NFM were prepared by electro-spinning of PA6/ biopolymer composites in formic acid using nozzle-less electro-spinneret. The potential of the prepared mats for sorption of Cr+6, Cr+3, Cu+2, and Pb+2 cations as well as anionic and cationic dyes from wastewater was assessed. The prepared composites were characterized by measuring their viscosity, nano-fibre diameter, pore size, thickness, and air permeability. The morphological structure of the electro-spun NFM was investigated by scanning electron Microscopy. Chemical and physical properties of the obtained mat were studied FTIR, TGA, DSC, and XRD. The capacity of the prepared NFM for sorption of cations and dyes depended on the mat composition and the nature of the adsorbed cation or dye.
 This work meets some environmental and economic demand by extraction of keratin and sericin from waste materials and their utilization in reinforcement of PA6 NFM for sorption of selected cations as well as dyes from textile effluents.

Sustainable synthesis of rose flower-like magnetic biochar from tea waste for environmental applications

IntroductionBiochar utilization for adsorption seems to be the most cost-effective, easy/fast approach for pollutants removal from water and wastewater. Due to the high adsorption properties, magnetic biochar proved to be efficient in the sorption of heavy metals and nutrients. Although there are several studies on development of magnetic biochars, there is a lack of research on development of high-performance magnetic biochar from food waste for removal applications. ObjectivesThis study aimed at preparing new classes of magnetic biochar derived from tea waste (TBC) for removal of heavy metals (Ni2+, Co2+), and nutrients (NH4+ and PO43−) from water and effective fertilizer (source of NH4+ and PO43−). MethodsStandard carbonization process and ultrafast microwave have been used for fabrication of TBCs. The removal of nickel, cobalt as the representatives of heavy metals, and over-enriched nutrients (NH4+ and PO43−) from water were tested and the removal kinetics, mechanism, and the effect of pH, dissolved organic matter and ionic strength were studied. Simultaneously, possible fertilizing effect of TBC for controlled release of nutrients (NH4+ and PO43−) in soil was investigated. ResultsUp to 147.84 mg g−1 of Ni2+ and 160.00 mg g−1 of Co2+ were adsorbed onto tested biochars. The process of co-adsorption was also efficient (at least 131.68 mg g−1 of Co2+ and 160.00 mg g−1 of Ni2+). The highest adsorbed amount of NH4+ was 49.43 mg g−1, and the highest amount of PO43− was 112.61 mg g−1. The increase of the solution ionic strength and the presence of natural organic matter affected both the amount of adsorbed Ni2++Co2+ and the reaction mechanism. ConclusionsThe results revealed that magnetic nanoparticle impregnated onto tea biochar, can be a very promising alternative for wastewater treatment especially considering removal of heavy metals and nutrients and slow-release fertilizer to improve the composition of soil elements.

Zirconia-Intercalated Kaolinite: Synthesis, Characterization, and Evaluation of Metal-Ion Removal Activity

AbstractThe intercalation of kaolinite through the insertion of ions or molecules amongst the structural aluminosilicate layers is a vital process in numerous clay-based applications and products. Layer neutrality and hydrogen bonding limits direct intercalation into kaolinite, other than for small molecules. Synthesizing zirconia-intercalated kaolinite is not a straightforward matter. To overcome this barrier, raw Egyptian kaolin (UnK) or its acid-activated product (HK) was sonicated and impregnated in aqueous ZrOCl2·8H2O solution followed by thermal treatment at various temperatures (100, 200, 300, and 500°C). The intercalation process was confirmed using various spectroscopic and analytical techniques. The direct intercalation of ZrO2 into the kaolinite layers was observed even through a mild thermal treatment (100, 200, and 300°C). The mechanism of intercalation was suggested to occur by binding ZrO2 to the Si/AlO groups with a preference for the acid-activated HK, causing variable enlargements of the basal spacing and producing very perturbed layers. Interestingly, the surface area increased by 250% as a result of zirconia intercalation. Scanning electron microscopy (SEM) images showed a remarkable improvement in the stacking order of the kaolinite particles. The impact of ZrO2 intercalation into kaolinite also enhanced its adsorption efficiency for Pb2+, Cu2+, and Cd2+ ions. Preliminary investigations showed that the zirconia-intercalated HK demonstrated a removal efficiency, which is three times greater than that of pristine HK. The adsorption tendency toward Pb2+ ions was greater than those of Cu2+ and Cd2+ and followed the order: Pb2+ >> Cu2+ > Cd2+. The study suggests that the chemical modification of kaolin by zirconia via a direct intercalation technique, which greatly improves its functionality as demonstrated by the selective sorption of heavy metal ions, is worthy of further study.

Magnetic Porous Geopolymer: A Cheaper and Efficient Environmental Tool for Heavy Metal Sorption

AbstractSorption of heavy metals is a crucial controller method for environmental pollution. Contamination by heavy metals is one of the most critical and discussed environmental issue nowadays that fits in the context of bioaccumulation. Some examples of these contaminants are lead, cadmium, and chromium. In order to avoid increasing the level of these contaminants in rainwater networks, the Brazilian Council of Environment (CONAMA) establishes that it is essential that industries that produce effluents remove these metals before returning the effluent to the network. Given this, a new technology is proposed for the removal of heavy metals. A magnetic nanocomposite is produced by adding maghemite nanoparticles to an aluminosilicate matrix and subjected to heavy metal‐contaminated effluents to sorption through this material. In order to evaluate the efficiency of removal of heavy metals by aluminosilicates, the effluents are analyzed by atomic absorption spectroscopy, and the results show a 99% sorption capacity. Finally, lethality tests, using Artemia salina, are performed. The best results are from the chromium and lead absorption tests.

Uranium and other heavy metal sorption from Moroccan phosphoric acid with argan nutshell sawdust

Argan nutshells, available in Morocco as a low-cost by-product from Argan oil production, were used to produce a sawdust biosorbent for the extraction of U and other heavy metals (Cd, As, Zn, Cu, Ni and Cr) from merchant-grade phosphoric acid (PA). Packed column (D = 20 mm, L = 250 mm, flowrate 1 mL/min) lab-scale experiments were carried out with three different solutions: (1) a synthetic heavy metals solution, (2) pure PA at different concentrations (0.85%, 8.5% and 85%) in water, and (3) merchant-grade PA from an industrial fertilizer plant in Morocco that was diluted with water to analyze different P2O5 contents (5%, 30% and 54%) and a U concentration of up to 157 ppm. The sawdust successfully adsorbed 99% of the U from (1) the synthetic solution and (2) the pure PA independent of the acid concentration. It further managed to adsorb more than half (54%) of U, 75% of Cd, 74% of As, 84% of Zn, 86% of Cu, 83% of Cr of the merchant-grade PA at 54% P2O5 content and a flow-rate of 1 mL/min. The sawdust was characterized by SEM and FTIR to understand the adsorption of metal ions. Column studies were carried out to know the breakthrough point. At breakthrough, the effluent volume was found to be 50 mL and the maximum adsorption capacity for U was found to be 0.93 mg/g. Heavy metal recovery using ANS does not seem to be promising as a result of the low (>10%) desorption rates if citric- or oxalic acid is used as was done in this study. Heavy metal extraction without direct recovery using ANS is promising and should further be investigated though.

Sorption studies of Cd and Cu on Brazilian alluvial soils

The Local Production Arrangement, located in the Pernambuco’s Agreste state, has been significantly developing the region's economy. Despite its importance, industrial activity has caused relevant environmental concerns regarding the disposal of textile effluents, especially from industrial laundries. This waste is made up of many chemicals, and among them are various types of heavy metals. The evaluation of the sorption behavior of contaminant transport mechanisms such as heavy metals is essential to assess the risk of contamination of alluvial aquifers. This study evaluated the sorption of heavy metals (Cu and Cd) in an alluvial sediment deposit in the Capibaribe River. Kinetics and isotherm experiments allowed the analyses of Cu and Cd sorption. Kinetics sorption showed an equilibrium tendency after 16 h for Cu and 18 h for Cd and was better described by a pseudo-second order model. The isotherm data were adjusted to the Linear, Freundlich and Langmuir models. Both linear and Freundlich models satisfactorily described sorption isotherms for the two pollutants. The metals in the study represent a risk of contamination of the groundwater of alluvial aquifers, mainly due to physicochemical attributes of the soil, such as high sand content (85%), low MO (2.1 g kg-1) and alkaline pH (8.2). The environmental conditions decrease absorption and facilitate metal mobility, greatly increasing the environmental risks inherent in pollutant leaching. Cu showed a higher affinity with the soil studied in all assays performed compared with the results of the tests for Cd.

Enlightening the characteristics of bioflocculant of endophytic actinomycetes from marine algae and its biosorption of heavy metal removal

The removal of toxic heavy metal ions from contaminated environments is a great challenge and requires an alternative rapid, efficient, economical bioremediation approach. Henceforth, bioflocculant producing endophytic actinobacterial sp. was isolated from heavy metal contaminated marine environments for heavy metal biosorption process. After molecular characterization, the isolated actinomycete starin was Nocardiopsis sp. GRG 3 (KT235642). It was indicated that the maximum flocculating activity of 80.90% with glucose, and yield is 4.52 g L1. The optimum flocculating activity was reached at pH 7 in the presence of CaCl2 ions. Further, the bioflocculent produced Nocardiopsis sp. GRG 3 (KT235642) was characterized by fourier transform infrared analysis spectra (FTIR) and displayed the presence of carboxyl, hydroxyl, amino groups and characteristic of more polysaccharide and protein. The heavy metal sorption by bioflocculant Nocardiopsis sp. GRG 3 (KT235642) was effectively removed 55.90% Cd, 85.90% Cr, 74.7% Pb, and 51.90% Hg. Therefore, this study was proved that the bioflocculant derived from endophytic actinobacteria, Nocardiopsis sp. GRG 3 (KT235642) as a effective alternative method for decreasing the heavy metals towards sustainable environmental management.

Nanoplastics Aggregation in Environment: Analytical Methods and Environmental Implications

The degradation of plastic debris may result in the generation of nanoplastics, which is an emerging environmental pollutant and widely existed in the earth. Compared with microplastics, nanoplastics have higher specific surface area for the sorption of organic pollutions and toxic heavy metals. Due to the small particle size, nanoplastics can be transported in organs and tissues of the human body, Posing a potential hazard to human health. However, due to the limitation of collection and analysis methods, there are more literatures on microplastics than on nanoplastics. This article reviews the analytical methods and potential hazards to the environment of nanoplastics. It summarizes and analyzes the recent research, and looks forward to the future research, so as to provide a reference for the continued research of nanoplastics.

Clean water production by non-noble metal/reduced graphene oxide nanocomposite coated on wood: Scalable interfacial solar steam generation and heavy metal sorption

Herein, a cost-effective, bifunctional, scalable, and highly efficient water-treatment material was prepared by coating iron/nickle (Fe/Ni)-reduced graphene oxide (RGO) nanocomposite on poplar wood which was used both as non-noble metal based photoabsorber in interfacial solar steam generation of seawater and as highly efficient heavy metal sorbent. The solar evaporation fluxes of 1.43 and 4.19 kg m−2h−1 under 1 and 3 sun (1 sun = 1 kW m−2), respectively were achieved by the most efficient photoabsorber (RGO200/FeNi-wood). The evaporation efficiency of the photoabsorber did not change significantly even after 20 cycles. After desalination by RGO200/FeNi-wood, a remarkable reduction in the salinity (4 order of magnitude), pH (8.1 to 6.2), and electrical conductivity (6000 to 2.25 µScm−1) was achieved. The cost per produced steam rate was calculated as 0.03 $ cm−3h under 3 sun which is comparable to the best double-layer devices reported in the literature. RGO200/FeNi-wood could act as a novel sorbent to remove Pb (II) completely from aqueous solutions.

Preparation of Cellulose/Chitin Blend Materials and Influence of Their Properties on Sorption of Heavy Metals

A series of biodegradable cellulose/chitin materials (beads and membranes) were successfully prepared by mixing cellulose with chitin in an NaOH/thiourea–water system and coagulation in a H2SO4 solution. The effects of chitin content on the materials’ mechanical properties, morphology, structure, and sorption ability for heavy metal ions (Pb2+, Cd2+, and Cu2+) were studied by tensile tests, scanning electron micrographs, Fourier transform infrared spectroscopy, and atomic absorption spectrophotometry. The results revealed that the cellulose/chitin blends exhibited relatively good mechanical properties, a homogeneous, microporous mesh structure, and the existence of strong hydrogen bonds between molecules of cellulose and chitin when the chitin content was less than 30 wt%, which indicated a good compatibility of the cellulose/chitin materials. Furthermore, in the same chitin content range, Pb2+, Cd2+, and Cu2+ can be adsorbed efficiently onto the cellulose/chitin beads at pH0 = 5, and the sorption capacity of the beads is more than that of chitin flakes. This shows that the hydrophilicity and microporous mesh structure of the blends are favorable for the kinetics of sorption. Preparation of environmentally friendly cellulose/chitin blend materials provides a simple and economical way to remove and recover heavy metals, showing a potential application of chitin as a functional material.

Bottom Ash Modification via Sintering Process for Its Use as a Potential Heavy Metal Adsorbent: Sorption Kinetics and Mechanism.

Heavy metal pollution in the environment is a critical issue, engendering ecosystem deterioration and adverse effects on human health. The main objective of this study was to evaluate heavy metal adsorbents by modifying industrial byproducts. The bottom ash was sintered and evaluated for Cd and Pb sorption. Three adsorbents (bottom ash, sintered bottom ash (SBA), and SBA mixed with microorganisms (SBMA)) were tested to evaluate the sorption kinetics and mechanism using a lab-scale batch experiment. The results showed that the highest sorption efficiency was observed for Cd (98.16%) and Pb (98.41%) with 10% SBA. The pseudo-second-order kinetic model (R2 > 0.99) represented the sorption kinetics better than the pseudo-first-order kinetic model for the SBA and SBMA, indicating that chemical precipitation could be the dominant sorption mechanism. This result is supported by X-ray photoelectron spectroscopy analysis, demonstrating that -OH, -CO3, -O, and -S complexation was formed at the surface of the sintered materials as Cd(OH)2 and CdCO3 for Cd and PbO, and PbS for Pb. Overall, SBA could be utilized for heavy metal sorption. Further research is necessary to enhance the sorption capacity and longevity of modified industrial byproducts.

Mesoporous Biopolymer Architecture Enhanced the Adsorption and Selectivity of Aqueous Heavy-Metal Ions.

Halloysite nanotubes (HNT) and ball-milled biochar (BC) incorporated biocompatible mesoporous adsorbents (HNT-BC@Alg) were synthesized for adsorption of aqueous heavy-metal ions. HNT-BC@Alg outperformed the BC, HNT, and BC@Alg in removing cadmium (Cd), copper (Cu), nickel (Ni), and lead (Pb). Mesoporous structure (∼7.19 to 7.56 nm) of HNT-BC@Alg was developed containing an abundance of functional groups induced from encapsulated BC and tubular HNT, which allowed heavy metals to infiltrate and interact with the adsorbents. Siloxane groups from HNT, oxygen-containing functional groups from BC, and hydroxyl and carboxyl groups from alginate polymer play a significant role in the adsorption of heavy-metal ions. The removal percentage of heavy metals was recorded as Pb (∼99.97 to 99.05%) > Cu (∼95.01 to 90.53%) > Cd (∼92.5 to 55.25%) > Ni (∼80.85 to 50.6%), even in the presence of 0.01/0.001 M of CaCl2 and Na2SO4 as background electrolytes and charged organic molecule under an environmentally relevant concentration (200 μg/L). The maximum adsorption capacities of Ni, Cd, Cu, and Pb were calculated as 2.85 ± 0.08, 6.96 ± 0.31, 16.87 ± 1.50, and 26.49 ± 2.04 mg/g, respectively. HNT-BC@Alg has fast sorption kinetics and maximum adsorption capacity within a short contact time (∼2 h). Energy-dispersive X-ray spectroscopy (EDS) elemental mapping exhibited that adsorbed heavy metals co-distributed with Ca, Si, and Al. The reduction of surface area, pore volume, and pore area of HNT-BC@Alg (after sorption of heavy metals) confirms that mesoporous surface (2–18 nm) supports diffusion, infiltration, and interaction. However, a lower range of mesoporous diameter of the adsorbent is more suitable for the adsorption of heavy-metal ions. The adsorption isotherm and kinetics fitted well with the Langmuir isotherm and the pseudo-second-order kinetic models, demonstrating the monolayer formation of heavy-metal ions through both the physical sorption and chemical sorption, including pore filling, ion exchange, and electrostatic interaction.

Prediction of the sorption efficiency of heavy metal onto biochar using a robust combination of fuzzy C-means clustering and back-propagation neural network

Heavy metal adsorption onto biochar is an effective method for the treatment of the heavy metal contamination of water and wastewater. This study aims to evaluate the heavy metals sorption efficiency of different biochar characteristics and propose a novel intelligence method for predicting the sorption efficiency of heavy metal onto biochar with high accuracy based on the back-propagation neural network (BPNN) and fuzzy C-means clustering algorithm (FCM), named as FCM-BPNN. Accordingly, the FCM algorithm was used to simulate the properties of metal adsorption data and divide them into clusters with similar features. The clustering results showed that the FCM algorithm simulated metal adsorption data's properties very well and classified them based on biochar characteristics and adsorption conditions. Afterward, BPNN models were well-developed based on these clusters, and their outcomes were then combined (i.e., FCM-BPNN). The results indicated that the FCM-BPNN model could predict heavy metal's sorption efficiency onto biochar with a promising result (i.e., RMSE of 0.036, R2 of 0.987, RSE of 0.006, MAPE of 0.706, and VAF of 98.724). Whereas the BPNN model, without optimizing the FCM algorithm, was proved with lower performance (RMSE = 0.050, R2 = 0.977, RSE = 0.011, MAPE = 0.802, and VAF = 97.662). These findings revealed that the FCM algorithm's presence impressively improved the BPNN model's accomplishment in predicting heavy metal's sorption efficiency onto biochar, and the proposed FCM-BPNN model can improve water/wastewater treatment plants' quality and provide a more efficient process for heavy metals with performance superiority.

HIGHLY EFFICIENT REMOVAL OF COPPER(II) IONS FROM AQUEOUS SOLUTION BY NICKEL 2-ETHYLIMIDAZOLATE

Nickel 2-ethylimidazolate was obtained and characterized, which is used in this work as a sorbent for the removal of copper (II) ions. The sample characterization was carried out by scanning electron microscopy, low-temperature nitrogen adsorption. It was found that the obtained sorbent is a microheterogeneous material with the size of individual particles in the range of 0.4-0.7 μm. Nitrogen adsorption isotherms in the pores of nickel 2-ethylimidazolate were obtained. It was found that when processing the experimental data in linear coordinates of TVFM, linearization is reached in coordinates lnV-lnPs/P, which indicates the predominance of mesopores in the structure of nickel 2-ethylimidazolate. The total pore volume was determined from the TVFM linear coordinates. It was 0.21 cm3/g. According to obtained differential pore size distribution, the most probable average pore radius corresponds to 7.5 nm. One of the main characteristics of nickel 2-ethylimidazolate as a sorbent, the surface area was determined by the A.V. Kiselev method and amounted to 703.56 m2/g. The efficiency verification of using nickel 2-ethylimidazolate in the heavy metal ions sorption processes was carried out by removal of copper(II) ions from aqueous solutions by the limited solution volume method at different contact times. The copper(II) sorption kinetics in the presence of nickel 2-ethylimidazolate was studied by processing experimental data in the first and second orders linear coordinates. It was found that the adsorption kinetics of copper(II) ions is described by a second order model, which indicated ion-exchange adsorption. Equilibrium adsorption capacity in the sorbent-solution system is reached at a contact time of 90-120 min.

Enhanced heavy metals sorption by modified biochars derived from pig manure

To enhance the sorption efficiency of heavy metals by modified biochar, biochars derived from pig manure at different pyrolyzing temperatures (300 °C, 500 °C and 700 °C) were oxidized and thiolated using H2O2 and 3-mercaptopropyltrimethoxysilane, respectively. The physicochemical properties of biochars and sorption kinetics, isotherms, and mechanisms for Pb and Cd were studied. Oxidation and thiolation decreased the aromaticity and ash content, and increased the polarity and the specific surface area and pore volume of biochars. Oxidation introduced oxygen-containing functional groups into biochars, and the oxidation reaction took place at CC bonds. The thiolation of oxidized biochar prepared at moderate-temperature had the highest sulfur content (4.43%) due to that this biochar was rich in oxygen-containing groups, which can act as the active sites for thiol groups loading. Sorption capacity of biochars for heavy metals increased by 2.58–4.22 times with the increase of pyrolyzing temperature, except the original biochar prepared at moderate-temperature, which had the highest Pb sorption capacity. The distribution coefficient of heavy metals onto modified biochars was enhanced by up to 85.4%. Oxidization treatment was more suitable for immobilization of low concentrations of Cd onto low- and moderate-temperatures biochars, while thiolation treatment was more suitable for immobilization of high concentrations of heavy metals. The sorption of heavy metals by biochars occurred via cation exchange, precipitation, cation-π EDA interactions and complexation. The contribution percentage of complexing with functional groups increased after modification. The results suggest that oxidization and thiolation treatments of animal manure biochars are promising methods for the treatment of heavy metals polluted environment.

Removal of Iron and Manganese from Palm Oil Mill Effluent (POME) using Activated Clinoptilolite Zeolite

The adsorption capacity of activated clinoptilolite zeolite for the removal of heavy metal ions; iron Fe(III) and manganese Mn(II) from palm oil mill effluent (POME) was investigated in this batch sorption study. The physicochemical properties of both raw clinoptilolite zeolite and POME effluent were first characterized before the modification of the zeolite is made, chemically and physically. The raw filtered POME has an initial pH of 4.56 which was acidic, whereas the natural zeolite has a slightly alkaline pH at 7.52. The effects of pH (5, 7 and 9), sorbent dosage (15, 20 and 25 g in 125 ml of effluent), contact time (15, 30, 45, 60, 120, 150, 180 and 200 minutes) and agitation speed (120, 150, 180 and 200 rpm) on the sorption of heavy metal ions were evaluated. The concentration of heavy metals was analyzed using AAS. The concentration of heavy metal ions for each parameter has decreased significantly after batch study. The adsorption of heavy metal ions increased with the increasing of pH and adsorbent dosages. Optimum percentage of metal removal and the amount of metal ions adsorbed by the zeolite were determined at 85% of Fe(III) and almost 92% of Mn(II) in the experiments.

Role of pore chemistry and topology in the heavy metal sorption by zeolites: From molecular simulation to machine learning

Zeolite frameworks can provide pores that enable selective heavy metals sorption, making these materials promising for energy-efficient heavy metals capture. In the present study, the adsorption of hazardous heavy metal ions on 242 zeolites have been investigated by employing molecular simulations and machine learning techniques, where the role of pores, topology, and chemical characteristics in the heavy metal sorption has been examined. The molecular simulation results show that only the zeolites with high diameter of pores exhibited appreciable loading of the cations. To unravel the encoded chemical information of the three parameters (total energy, pore size and average volume) on how each influence the loading capacity of the heavy metals, boruta algorithm; a wrapper based built around random forest classier was employed to rank these parameters. In light of the forgoing, total energy accounts for the highest contribution for the sorption of heavy metals. Compared to the pore size, the average volume was rejected by the random forest classier algorithm, which implies that the individual pore size on the surface of each of the best performing zeolite framework is responsible for the adsorption of heavy metals with relatively high sphere diameter instead of total volume of each zeolite.

Treatment of a mining water effluent for the sorption of heavy metal ions using polymer composite beads in a continuous column

AbstractThe performance of novel chitosan‐poly(vinyl alcohol) gel beads was evaluated removing lead, cadmium and chromium from mining‐influenced groundwater (MIGW) under hydrodynamic conditions employing column sorption experiments. To elicit the efficiency of the synthesized materials, the sorbent bed height within the packed column and volumetric flow were varied; the column configuration was changed using packed and fluidized arrangements. The fluidized bed configuration presented higher sorption efficiency for Pb, Cd and Cr ions than the fixed bed configuration: 78%, 52% and 62% against 60%, 35% and 37%. The packed bed data were processed using the Clark, Dose–Response, Yoon‐Nelson and Woldborska models. The best fitting was obtained with the Dose–Response model. The experimental output confirmed the effective reduction of the harmful metals in MIGW at a very short breakthrough time from 3 to 15 min, which is strategic due to the global effects on both human health and environment.

Using the mineral component of building refuse in heavy metals sorption from their mixture

The sorption properties of the sand-breakstone mixture based on the mineral component of building refuse of the 0-10 mm fraction with respect to Pb2+, Zn2+, Cu2+, Ni2+, Cd2+ and Hg2+ ions were studied using atomic absorption spectroscopy. The mechanisms of accumulation of heavy metal ions on the surface of the mixture particles are described. It was found that after washing the contaminated material distilled water, the residual concentration of metals in the filtrate does not exceed the established sanitary and hygienic standards. The practical value of the work lies in the possibility of applying the results in reclamation of technogenic formations or production of materials for the technical stage of reclamation using technogenic soils.