Metal Concentration In Solution Research Articles

Brick sand particles as an adsorbent in column chromatography to remove heavy metals from solution

The column chromatography method was used with brick sand particles as an adsorbent for the removal of heavy metals (Cr, Fe, and Pb) from the aqueous solution. These metals can pollute water, and soil and also come in contact with the food chain, causing life-threatening health issues in the human body. The pore volume and the specific surface area of the brick sand particles were determined using the standard method which was 44.41% and 29.4 m2/g respectively. The different concentrations of toxic metals in the water solution were considered to determine the adsorption capacity of the adsorbent. The adsorption methods were able to remove about 94% of Cr, 24% Pb, and 69% Fe from the aqueous solution. From the investigation results, we may conclude that raw brick sand particles can play a vital role as an adsorbent in the treatment of heavy metal-contaminated wastewater. Moreover, the saturated adsorbent can be used as an element of construction materials to prevent further pollution. Bangladesh J. Sci. Ind. Res. 59(1), 47-54, 2024

Extraction of Rare Earth Elements from Chloride Solutions Using Mixtures of P507 and Cyanex 272

In this study, the extraction of rare earth elements (REEs) from chloride solutions after leaching REE carbonate concentrate with solutions of the mixtures of P507 (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester) and Cyanex 272 (bis(2,4,4-trimethylpentyl)phosphinic acid) (1:1) at various concentrations was experimentally studied. It was shown that the distribution ratios of all REEs decrease with the increasing concentration of these metals in the initial solution, which is associated with the loading of the organic phase. The most significant improvement in the extraction is observed for the heavy group of rare earth elements. The extractability of REEs increases with the increasing atomic number of the element, as is typical for the extraction of these metals with acidic organophosphorus extractants. The data obtained show that the separation factors of adjacent rare earth elements decrease slightly with the increasing concentration of metals in the initial aqueous solution. Increasing the concentration of the extractant mixture does not have a significant effect on the values of the adjacent REE separation factors. The data obtained on the distribution ratios and separation factors made it possible to propose a flow sheet for the separation of rare earth elements with the production of Y, Ho, Tb and Dy.

Ultrafast adsorption of hexavalent chromium from aqueous effluents using covalent triazine frameworks

We have synthesized low-cost high performance covalent triazine framework (CTF) through Schiff base reaction of melamine and terephthalaldehyde with different proportions of the reactants. The synthesized adsorbents showed excellent capacity for adsorption of Cr (VI) at acidic pH while almost negligible adsorption at higher pH. The adsorbent displays excellent reusability, with a little decrease in adsorption capacity with the increasing number of cycles. Moreover, Cr (VI) the adsorption is unaffected by the presence of 50–500 times higher concentration of alkali metal and halide ions in solution, while sulphate ions demonstrate shielding behavior decreasing the adsorption capacity. Mechanistic studies indicate electrostatic attractions, ion exchange and reduction being responsible for the adsorption mediated by abundant nitrogen sites that also imbibes the adsorbent with high capacity. The adsorbent was also utilized to recover chromium from an industrial electroplating effluent, which demonstrates applicability of material for practical applications.

Optimization of Chromium (VI) Adsorption using Microalgae Biomass (Spirulina sp.) and its Application in Leather Tannery Waste

<p class="E-JOURNALAbstractBodyEnglish">This study was conducted to examine the adsorption of Cr (VI) metal using Spirulina sp (inactive) biomass and its application in leather tannery wastewater. The treatment was carried out to determine the influence of independent variables on Cr (VI) adsorption with variations in pH, contact time, and metal solution concentration. The values of the solution pH, adsorption time, and concentration of the best metal solution were used to determine the center points of the optimization variables through Response Surface Methodology (RSM). The results showed that based on the FTIR test, macromolecules present in Spirulina sp biomass included amino, carboxylate, and hydroxy groups. The combination of factor variables that produced the optimum response was at pH 3.165, contact time of 66.58 minutes, and Cr (VI) metal ion solution concentration of 22.9 mg/L, resulting in a Cr (VI) adsorption efficiency of 69.66%. The adsorption pattern was included in the Freundlich adsorption isotherm, and the application of Spirulina sp biomass adsorbent to tannery waste reduced the concentration of Cr (VI) from 3.9 g/L to an undetectable level at <1.4 g/L.</p>

Application of Diffusive Gradients in Thin-films (DGT) for assessing the heavy metals mobility in soil and prediction of their transfer to Russula virescens

Although edible mushrooms are considered a source of many beneficial nutrients for human, they can also represent a risk to health due to their capacity to accumulate heavy metals. In this study, the total dissolved in soil solution and labile concentrations of heavy metals (Cd, Pb, Cu, Zn, Co, Cr, Mn, Ni, and Fe) in soil were measured and correlated with their concentrations accumulated in Russula virescens wild mushrooms. The diffusive gradient in thin films (DGT) technique was used to measure the labile metals content in the soil (CDGT), and corroborated with the metals concentrations in soil solution (Csoln) was used to calculate an R-value, which can estimate the metals resupply from soil solid phase when they are uptake by mushroom. The DGT-labile metal concentrations decreased in the order Mn > Fe > Zn > Cu > Co > Ni > Cd ≅ Pb > Cr. The R-values, calculated as the ratio between CDGT and Csoln decreased in the order: Cd (0.50) > Zn (0.37) > Pb (0.33) > Cu (0.24) ≅ Ni (0.24) ≅ Co (0.23) > Mn (0.16) > Fe (0.12) > Cr (0.04). For the first time, we compared the R-values with the bioaccumulation factors (BAFs) in mushrooms, and it was observed that, a similar increasing trend of BAFs with the R-values exists, thus the capacity of the soil solid phase to fast re-supply metals to soil solution increases BAFs. Although the soil samples were not contaminated with heavy metals above the legislative limits, the concentrations of heavy metals accumulated in mushrooms were high enough to pose risks for humans, mainly for children, due to their Cu content.

Characterization of Green synthesised Iron nanoparticles and application of synthesised Iron nanoparticles as an effective catalyst for the removal of Carcinogenic metals in aqueous solution

The heavy metals such as chromium (Cr), lead (Pb) and cadmium (Cd) are considered as serious toxicants and act as carcinogenic agents that cause serious cancers to humans. The use of these heavy metals drastically increased in various industrial applications and subsequently increased the risk of contamination of these heavy metals in soil, water etc. To minimize the negative effects of these heavy metals, there is a need to reduce these heavy metals concentrations in environment samples. Hence this study focused to fabricate iron nanoparticles using Diospyros chloroxylon (Roxb.) for the removal of carcinogenic metals in water. The crystal structure, size and morphology of the nanoaprticles were evaluated and it was found that the particles were of rod shape with smooth surface and rhombohedral phase structure with an average particle size of 24 nm that contains 71.91 % of elemental iron. The heavy metal sorption experiments was conducted using selected concentration of heavy metal solution at various pH ranges, time and agitation rate. The maximum adsorption removal was 95.36 %, 98.42 % and 92.80 % within 120 min equilibrium time for Cr, Pb and Cd respectively suggesting that the nanoparticles possess high adsorption efficiency. The adsorption process follows pseudo-first order reaction kinetics with correlation coefficient of 0.978, 0.994 and 0.994 with rate constant (K) of 0.140, 0.280 and 0.108 respectively for Cr, Pb and Cd. The results suggest that the synthesized iron nanoparticles were biocompatible, stable and reusable that can be effectively utilized as promising agents for the removal of carcinogenic heavy metals in polluted water.

Kinetics of heavy metal ions removal from aqueous solutions using synthesised composite hybrid cation exchanger

ABSTRACT Hybrid organic–inorganic materials make it possible to combine beneficial organic and inorganic properties into a single molecular-scale composite. In this study, the removal efficiency of synthesized organic–inorganic hybrid cation exchanger: nylon-6,6, Zr (IV) phosphate with respect to Cu2+, Zn2+ and Cd2+ has been investigated in order to take into account its potential use to clean up wastewaters from heavy metals. Metal concentrations in solution of 0.02 and 0.2 mol/L were used in the batch technique. For both lower and higher initial concentration, the process was fitting to both first and pseudo-first-order-kinetic model, while it is also consistent with the intra-particle diffusion model. Particle diffusion is the rate-limiting step in the multistep process that is primarily controlled by external mass transfer. Moderate activation energy values confirmed that the process is a combination of both physisorption and chemisorption. The order of removal may be presented as Cu2+ > Zn2+ > Cd2+.

A Prominent Streptomyces sp. Biomass-Based Biosorption of Zinc (II) and Lead (II) from Aqueous Solutions: Isotherm and Kinetic

Traditional freshwater sources have been over-abstracted in the worldwide crisis of water scarcity. Effluents have extremely high amounts of Zn2+ and Pb2+, according to an investigation of wastewater samples taken from several industrial zones. However, these heavy metals are among the most harmful to both humans and wildlife that are currently known. Streptomyces sp. is utilized in this study as a biosorbent to biosorb Zn2+ and Pb2+ from single and binary aqueous solutions. Several factors, such as biomass concentration (0.25–4 g), metal solution concentration (5–50 mg L−1), solution pH (2–5), and contact time were standardized. Streptomyces sp. biomass was able to extract 93% Pb2+ and 91% Zn2+ from a single and 95% Pb2+ and 97% Zn2+ from a binary metal aqueous solution containing 25 mg L−1 and pH 4. The highest adsorption capacity in both single and binary sorption experiments was determined to be shared by Zn2+ and Pb2+. The biosorbent’s metal adsorption increased from 0.48 to 4.56 mg g−1 for Pb2+ and from 0.21 mg g−1 to 4.65 mg g−1 for Zn2+ when the metals were present singly, and from 0.44 to 4.18 mg g−1 for Pb2+ and from 0.41 mg g−1 to 5.67 mg g−1 for Zn2+ when the metals were present in binary form. The amount of metal ions was raised from 5 to 50 mg L−1. Correlation coefficient (R2) values indicate that the adsorption pattern for Zn2+ and Pb2+ followed Freundlich isotherm R2 > 0.9543 for single and 0.9582 for binary sorption system. In order to remove Zn2+ and Pb2+ from an aqueous solution, Streptomyces sp. is a potential and different source of adsorbents.

Технология извлечения полезных компонентов из горючих сланцев месторождения Актау

This paper describes technologies for processing of oil shales and determines parameters of thermal decomposition without oxygen access (pyrolysis) and hydrometallurgical methods for extracting useful components. The following methods are presented: leaching to extract valuable components into a sulfuric acid solution, and selective extraction to ion-exchange resins by sorption of valuable components of vanadium and molybdenum. The presented methods are not implemented on an industrial scale, since there is no oil shale processing in the Republic. Perspective technological schemes of oil shale ash processing are analyzed. The process involves the addition of sodium chloride to the process of thermal decomposition without access to oxygen (pyrolysis). The resulting ash is leached in vats with sulfuric acid 160 g/l, at room temperature, T : W = 1 : 5, duration 60 minutes. The resulting metal-bearing sulfuric acid solution is filtered and sent to sorption and precipitation. Extraction of vanadium and molybdenum into solution is more than 60–70 %. It should be noted that with an increase in the consumption of sulfuric acid over 160 g/l, the concentration of metals in the productive solution does not increase. The ion-exchange resins of the English company PUROLITE were used to extract metals from the productive solutions of leaching of oil shale ash from the Aktau deposit: for the extraction of molybdenum — A-100 Mo grade, and vanadium — A-109 grade.

Study on the co-pyrolysis behaviors of sewage sludge and Enteromorpha prolifera and the adsorption mechanism of Cr(VI) in water using pyrolysis residue

The thermal–chemical conversion method has significant potential for the recovery of organic matter present in sewage sludge (abbreviated as SS), offering broad market prospects. In this study, a novel approach is proposed for the preparation of a composite adsorbent, named SS-EP, derived from the co-pyrolysis residue of sewage sludge and Enteromorpha prolifera. An orthogonal experiment was designed to investigate the performance of the adsorbent, and the results revealed that the optimal conditions were achieved when the SS proportion was 40%, the concentration of zinc chloride was 0.1 mol/l, the pyrolysis temperature was 500 °C, and the pyrolysis time was 30 min. Notably, the SS-EP composite adsorbent exhibited pronounced efficacy in the removal of Cr(VI) under both acidic and neutral conditions, achieving a removal rate exceeding 97%. Furthermore, the concentration of heavy metals in the leaching solution of the adsorbent was found to be significantly lower than the limit specified in the GB5085.3-2007 standard. Regeneration experiments demonstrated that even after the third regeneration, the SS-EP composite adsorbent maintained a removal rate of 70% for Cr(VI).

Construction of layered double hydroxides on wood surfaces for wood coloring

Wood dyeing usually requires a large concentration of metal solution, which when released to the atmosphere as waste liquid, causes pollution. In this study, a metal-organic framework (MOF) with micron-size structure was in-situ grown on a wood surface as a template and precursor for a layered double hydroxide (LDH). The LDH had a nanoscale structure and was generated on the wood surface from ultra-low concentration NiCl2 solution. The generation was based on a hydrolytically induced exchange process between the MOF and hydroxide ions. The results of following this procedure showed that petal-like Co/Ni-LDH with micro-nano composite structure was formed on the wood surface. Due to the LDH, a uniform light green color was formed on the wood surface at a reaction temperature and time of 60 ℃ in 34 min, respectively. To improve the hydrophobicity of the LDH layer, a long chain alkyl with low surface energy was introduced into the lamellae from a sodium stearate solution, constructing a superhydrophobic layer on the wood surface. The modified wood surface showed excellent UV light aging and water resistances. Moreover, Ni2+ was replaced with Mn2+, Fe3+, Cu2+, and Zn2+ ions and dark brown, yellow, blue, and white colors, respectively, were formed on wood. The present method is also suitable for other wood. Wood surface color adjusted by LDH uses low concentration of metal salt solution and proved to be a mild and green wood color toning method.

A Statistically Validated Electrochemical (Conductometric) and Spectroscopical Study of Some Metal Ligand Complexes for Prospective Biological Action

The present electrochemical study deals with the evaluation of a complexation process involving different metal and ligands and its physicochemical properties to find out the ligand- metal ratio of complex in solution. For the determination of complexing nature “Monovariation method” have been used to ascertain the ligand metal ratio in the complex. The stability constant of the formed complexes were calculated by conductance measurement using Modified Job’s method (Turner Anderson Method). The analysis had been carried out by using conductometric principle and the final outcome of the experiment may influenced by temperature and with the ionic concentration of metal and ligand solution. Free energy change values were determined to find out the feasibility of the complexation process. One of the method was validated statistically by using system and method precision parameters. Lastly the complexes was been assayed by using a specific chromogenic agent with a specific spectroscopic technique that may give biological action in future.

An IoT-Based Data-Driven Real-Time Monitoring System for Control of Heavy Metals to Ensure Optimal Lettuce Growth in Hydroponic Set-Ups.

Heavy metal concentrations that must be maintained in aquaponic environments for plant growth have been a source of concern for many decades, as they cannot be completely eliminated in a commercial set-up. Our goal was to create a low-cost real-time smart sensing and actuation system for controlling heavy metal concentrations in aquaponic solutions. Our solution entails sensing the nutrient concentrations in the hydroponic solution, specifically calcium, sulfate, and phosphate, and sending them to a Machine Learning (ML) model hosted on an Android application. The ML algorithm used in this case was a Linear Support Vector Machine (Linear-SVM) trained on top three nutrient predictors chosen after applying a pipeline of Feature Selection methods namely a pairwise correlation matrix, ExtraTreesClassifier and Xgboost classifier on a dataset recorded from three aquaponic farms from South-East Texas. The ML algorithm was then hosted on a cloud platform which would then output the maximum tolerable levels of iron, copper and zinc in real time using the concentration of phosphorus, calcium and sulfur as inputs and would be controlled using an array of dispensing and detecting equipments in a closed loop system.

Isothermal study on sorption of lead from synthetic solution using Liagora viscida

This paper deals with the preparation, characterization, and isothermal study on lead removal from synthetic solution using an algae Liagora viscida. The sorption experiments were performed by batch mode of operation and the parametric conditions studied are pH (2–8), contact time (1–180 min), and initial metal solution concentration (20–200 mg/L). The surface morphology of the Liagora viscida has been described using Scanning electron microscopy (SEM). Isothermal study confirmed that the data is well fitted by Freundlich isotherm. In summary, the inexpensive marine algae Liagora viscida proved as an excellent sorbent for lead removal from synthetic solution.

Experimental study on adsorption properties of functional magnetic nanomaterials for heavy metal pollutants

In order to effectively remove heavy metal pollutants and improve the quality of the ecological environment, the experimental study on adsorption properties of functional magnetic nanomaterials for heavy metal pollutants was studied. Magnetic nano-Fe3O4 materials were prepared by hydrothermal method. Fe3O4, Fe3O4@SiO2 and 3NH2-Fe3O4@SiO2 magnetic nanomaterials were obtained by functional modification. The adsorption properties of functionalised magnetic nanomaterials for Cd(II) and Pb(II) in water were analysed by batch test. The results show that 3NH2-Fe3O4@SiO2 has the highest adsorption capacity for Cd(II) and Pb(II); with decreasing temperature, the order of adsorption capacity for Pb(II) is Fe3O4 > Fe3O4@SiO2 > 3NH2-Fe3O4@SiO2. The Langmuir adsorption isotherm model can better fit the adsorption process of functionalised magnetic nanomaterials to Cd(II) and Pb(II) solutions. In different initial heavy metal solution concentration systems, the materials can promote the adsorption of Cd(II) and Pb(II) adsorption.

GROWTH EVALUATION OF CUCUMIS SATIVUS L. (CUCUMBER PLANT) IN ARSENIC AND CHROMIUM TREATED SOILS

Evaluation of the growth of Cucumis sativus in arsenic (As) and chromium (Cr) treatedsoils was carried out. Parameters measured were germination, plant height, number ofleaves, relative water content and total chlorophyll. The concentrations of metalsolutions applied were 0, 30, 60, 120 and 240 ppm of arsenic and chromium saltsseparately. The study was conducted as potted field experiment. The treatments werereplicated four times. Three days after planting (DAP), C. sativus seeds germinated inall soil treatments. The highest percentage germination was obtained in controltreatments 15 DAP. The metal treatments depressed germination. Similarly, plantheight was depressed significantly by As and Cr treatments (?=0.05). Plant heightvalues recorded for 240 ppm As and 240 ppm Cr were 24.1% and 36.5% of theirrespective values for control. Differences in number of leaves produced per plants werefound to be statistically significant under arsenic treatment only. The values obtained forrelative water content and total chlorophyll showed that plants grown in As and Crtreated soils were inhibited. Generally, plants grown under control conditions gavehigher values. From the growth parameters evaluated, arsenic treatments was moretoxic to Cucumis sativus than chromium treatments.

Isotherm, Kinetic, and Selectivity Studies for the Removal of 133Ba and 137Cs from Aqueous Solution Using Turkish Perlite.

The efficiency of 133Ba and  137Cs removal from aqueous solution is vital to mitigate ecological concerns over spreading these radionuclides in the environment. The present work focused on the use of Turkish perlite for the sorptive removal of  133Ba and  137Cs from aqueous solution by the radioindicator method. Perlite was characterized by XRF, XRD, FTIR, SEM-EDX, and BET analyses. The maximum percentage removals of 88.2% and 78.7% were obtained for  133Ba and  137Cs at pH 6 and pH 9, respectively. For both ions, the sorption equilibrium was attained relatively rapidly. Experimental kinetic data were well described with pseudo-second-order and intraparticle diffusion models. The uptake of both ions increased with the increase in metal concentration (1 × 10-5 to 5 × 10-2 mol/L) in solution. The maximum uptake capacities of  133Ba and  137Cs were found to be 1.96 and 2.11 mmol/g, respectively. The effect of competing ions decreased in the order of Ca2+>K+>Ni2+>Na+ for  133Ba sorption, whereas for  137Cs sorption, the order was determined as Ca2+>Ni2+>K+>Na+. Selectivity studies pointed out that sorption of  133Ba onto perlite is preferable to  137Cs. Therefore, Turkish perlite is a promising, cost-effective, and efficient natural material for the removal of  133Ba and  137Cs from relatively diluted aqueous solution.

Study on leaching characteristics of MSWIFA in different pH environment

The change of leaching solution of waste incineration fly ash (MSWIFA) after shaking under different initial extractant pH was studied, and the change trend was compared with that of fly ash under different extractant concentrations. In addition, the leaching characteristics of heavy metals were analyzed under the two methods. The results showed that the pH change of the initial extractant can not truly simulate the environment of fly ash landfill, and the former can not reflect the pH of the final leaching solution. Changing the initial extractant concentration within a certain range can gradually change the final leaching solution from alkaline to acidic, which can truly reflect the environmental changes experienced by fly ash in the landfill (such as rainstorm scouring, drought and other environment). The leaching concentration of heavy metals in the leaching solution obtained by shaking fly ash under different acetic acid concentrations reflects the actual leaching characteristics of heavy metals under different pH conditions, in which Pb and Zn are amphoteric leaching, and the other metals are cationic leaching.

Study on leaching characteristics of MSWIFA in different pH environment

The change of leaching solution of waste incineration fly ash (MSWIFA) after shaking under different initial extractant pH was studied, and the change trend was compared with that of fly ash under different extractant concentrations. In addition, the leaching characteristics of heavy metals were analyzed under the two methods. The results showed that the pH change of the initial extractant can not truly simulate the environment of fly ash landfill, and the former can not reflect the pH of the final leaching solution. Changing the initial extractant concentration within a certain range can gradually change the final leaching solution from alkaline to acidic, which can truly reflect the environmental changes experienced by fly ash in the landfill (such as rainstorm scouring, drought and other environment). The leaching concentration of heavy metals in the leaching solution obtained by shaking fly ash under different acetic acid concentrations reflects the actual leaching characteristics of heavy metals under different pH conditions, in which Pb and Zn are amphoteric leaching, and the other metals are cationic leaching.

Immobilization of exopolymeric substances from bacteria for metal removal: A study on characterization, optimization, reusability and toxicity

This study investigated the immobilization of exopolymeric substances (EPS) from Bacillus cereus using sodium alginate to form EPS beads for metal removal. The EPS beads were characterized and their optimum biosorption conditions established (biosorbent dosage, initial metal concentration and pH of metal solutions). The EPS beads were also tested for reusability by using them continuously for five metal removal cycles with desorption process in between cycles. The toxicity of the treated metal solutions was tested by phytotoxicity tests. Results revealed that EPS beads demonstrated significantly higher metal removal efficiency (Pb: 99.26%, Cr: 50.73%, Cu: 48.94%, Zn: 29.81%, Cd: 20.29%) compared to plain alginate beads (without EPS) (Pb: 84.45%, Cu: 31%, Cr: 28.37%, Zn: 11.91%, Cd: 9.37%). SEM-EDX analysis detected Cu, Pb, Zn, Cd and Cr on the surface of EPS beads. Optimum conditions for Pb removal by EPS beads were from the use of 0.1 g of biosorbent at 100 mg/L initial metal concentration and pH 5. By contrast, Cu, Zn, Cd and Cr were optimally removed by 0.3 g of biosorbent at 25 mg/L initial metal concentration and pH 5. EPS beads can be reused up to five times while maintaining a high rate of metal removal efficiency (Pb- 99.52%, Cr- 89.23%, Cu- 89.17%, Zn-52.52%, Cd-39.12%). This was achieved through desorption with nitric acid that consistently recovered 76–93% of the metal adsorbed. FTIR analysis reveals that nitric acid is capable of restoring the functional groups present within EPS beads, allowing it to bind with metal ions in repeated cycles. Metal solutions treated with EPS beads were less toxic as seedling shoots (pre-treated: 0–10 cm, post-treated: 1.2–18.1 cm) and roots (pre-treated: 0–7.8 cm, post-treated: 0.8–15.1 cm) grew well, which suggested that reduced levels of metals led to reduced phytotoxicity. This study provides an insight into the use of EPS beads for metal removal, highlighting the benefits and reusability of the beads for future wastewater treatment.