heavy metals

In this study, ammonium persulfate was used to initiate the graft copolymerization reaction of methacrylic acid and itaconic acid onto starch. The effect of different parameters on grafting efficiency was investigated. The so obtained St-co-MMA/IA with the highest graft efficiency, was crosslinked by N,N-methylene bisacrylamide (MBA), glutaraldehyde (GLA), ethylene glycol dimethacrylate (EGDMA) and buthylene glycol dimethacrylate (BGDMA) individually using different amounts of crosslinker agents. The synthesized hydrogels were characterized by swelling studies, field emission scanning electron microscopy (FESEM), thermal gravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). The crosslinked hydrogels were used for the removal of the heavy elements Pb2+, Fe2+ and Co2+ from its aqueous solution by adsorption. It was experimentally confirmed the metal uptake, obtaining the higher adsorption capacity (qe = 34.81 mg/g) for the product prepared with BGDMA crosslinker.

Heavy metals such as cadmium (Cd) and lead (Pb) are toxicants that negatively impact the immune system, enhancing systemic inflammation and disrupting the balance between pro-inflammatory and regulatory processes. They contribute to the reduction of CD4+ T-lymphocytes and regulatory T-cells (Treg), which is associated with an increased risk of chronic inflammation and autoimmune disorders. These effects arise from heavy metals' ability to disrupt proliferation and induce apoptosis of immune cells, as well as alter the expression of key regulatory markers such as FoxP3. In this regard, the aim of the present study was to investigate the effects of Cd and Pb on the course of aseptic inflammation (SI), as well as the possibility of immune modulation of identified disorders. The study was conducted on 5 groups of animals, with 90 outbred male rats weighing 180-220±20g, kept under standard vivarium conditions on a regular diet. In experimental animals, intoxication was induced by administering Cd and Pb at a dose of 2.5 mg/kg body weight orally for two weeks, after which aseptic inflammation was modeled in the animals. In this work, the activity of CD4+, CD4+CD25+ (activated T-cells) and CD4+FoxP3+ was studied using flow cytometry. This study aimed to compare the effectiveness of two synthesized compounds — Complex and MHF-19 — for correcting disorders caused by the combined effects of Cd and Pb. The obtained results show that both compounds promote the restoration of CD4+, CD4+CD25+ and CD4+FoxP3+ cell populations; however, their mechanisms of action differ significantly. Complex provides rapid suppression of inflammatory response and restoration of T-cell populations, which is consistent with previous data on its universal immunomodulatory action. Meanwhile, MHF-19 exhibited a more pronounced and sustained effect on Treg, manifesting as in an increase in the proportion of CD4+FoxP3+ cells and restoration of immune homeostasis with long-term use. Thus, MHF-19 demonstrated advantages in correcting chronic inflammation, especially in cases of regulatory mechanism disorders. The results underscore the promise of using MHF-19 for correcting inflammatory conditions caused by toxic effects of heavy metals and for managing chronic inflammatory processes.

In this study, carbon paste fabricated and modified a novel sensitive voltammetric sensor based on UiO-66/TiO2 MOF nanocomposite through the solvothermal method. The electrode surface morphology and enhancement study were performed through FESEM and FT-IR. The electrochemical behavior of the modified electrode was evaluated using cyclic voltammetry in the [Fe (CN)6]3-/4-solution and represented good electrocatalytic activity due to the synergy result of TiO2 and UiO-66. For quantitative analyses, differential pulse voltammetry was used under optimal conditions. The calibration curves show linear response in the concentration range of 2-100 μM with the lowest limit of detection of 0.851 µM and 0.436 µM were obtained for Pb2+ and Cu2+, respectively. The sensor exhibited high sensitivity and selectivity, good reproducibility, desirable stability, and excellent performance in real samples.

An experiment was conducted to explore the potential use of Coconut Shell HydroChar (CSHC) using batch adsorption. CSHC-LDH (Mg-Al) is mixed with layered double hydroxide (LDH) to remove Ni (II), Cd (II), and Zn (II) from a ternary-metal solution (with a mixing ratio of 0.5:0.3:0.2). We investigated the effects of initial concentrations, pH, adsorbent dosages, and contact time through adsorption kinetic and isotherm studies. The optimal conditions that give higher removal percentages were: pH of 6 and 4, adsorbent dose 1 and 0.7 mg, initial metals concentration 250 mg/L, and the equilibrium time of 90 min for CSHC and CSHC/MgAl-LDH, respectively. The CSHC and CSHC/MgAl-LDH composite revealed a strong sorption ability to Cd (II), Ni (II), and Zn(II) in aqueous solutions with the Langmuir maximum adsorption capacity of 188.67, 204.08, and 222.22 mg/g and 312.5, 344.82, and 357.14 mg/g, respectively. The adsorption kinetic study revealed that the adsorption process followed second-order kinetics. The batch experiment results showed that the CSHC and CSHC-Mg-Al LDH were effective in the simultaneous removal of Ni (II), Cd (II), and Zn (II) to a significant extent. The CSHC-Mg-Al LDH composite has demonstrated considerable promise in removing heavy metals from wastewater. It offers the benefits of easy synthesis and exceptional adsorption capability.

The presence of multiple contaminants often complicates treatment processes due to possible interactions and competition for binding sites. Focusing on a binary system allows researchers to explore these complexities and develop more effective treatment strategies. The modified bentonite may exhibit selective adsorption towards lead and cadmium ions in binary mixtures, effectively removing these pollutants from contaminated water or solutions. This study investigates the adsorption potential of Cd (II) and Pb (II) ions from aqueous solutions using purified bentonite and modified Algerian bentonite with Aliquat 336. The characterization of the bentonite surface, before and after modification, was conducted using BET, IR, and XRD analysis techniques. The experimental parameters influencing the adsorption process were examined. Results revealed that the specific surface area of natural bentonite, purified bentonite, and B336 Aliquat 336-bentonite was 47.20 m2/g, 91 m2/g, and 29.71 m2/g, respectively. The advantage of manufacturing 336 bentonite over purified bentonite is the increased distance between the layers, which led to enhanced maximum absorption capacity (31.04 mg/g for lead (II) and 25.03 mg/g for cadmium (II) using an aliquot of 336 bentonite. At the same time, it was 29.35 mg/g for lead (II) and 17.66 mg/g for cadmium (II) using purified bentonite). The equilibrium isotherms were best described by the Langmuir adsorption isotherm model. Furthermore, the modified bentonites exhibited effective desorption performance for cadmium using various stripping eluents (HNO3, HCl, H2SO4, and CH3COOH) while retaining Pb (II) ions. This demonstrates their potential as efficient adsorbents for heavy metals removal from contaminated environments, also, the combination of Algerian bentonite and Aliquat 336 likely creates a synergistic effect, leading to improved adsorption performance compared to unmodified bentonite or other sorbents.

The current research aimed to absorb heavy metal ions (Cu2+ and Pb2+) from wastewater. The hydrogel of acrylamide (AAm) and acrylamide-2-methylpropanesulfonic acid (AMPS) was prepared in different molar ratios of feed compositions (1:1, 1:2 and 1:0.25) by the free radical polymerization method. Potassium persulfate (KPS) was used as an initiator, and N, N'methylene-bis-acrylamide was used as a crosslinking agent at 70°C for seven hours.  AAm is a neutral monomer, and AMPS is a solid acidic monomer. Strong complexes were obtained when two monomers with different molar ratios of feed composition were mixed. The complex was analyzed by UV-Vis spectroscopy. The swelling properties of the prepared hydrogels were investigated at different pH values, temperatures, and ionic strengths. Fourier transform infrared (FT-IR) and thermogravimetric analysis (TGA) were used to study the hydrogels' structural behavior and thermal stability. The diffusion phenomenon was investigated for the prepared hydrogels at a pH of 7, considering the non-Fickian state. The Cu+2 and Pb+2 adsorption from wastewater by the prepared hydrogels at different mole ratios of a feed composition was investigated by Atomic Absorption Spectrometry (AAS). Moreover, the morphology of the hydrogel was evaluated by Scanning Electron Microscopy (SEM). The surface adsorption fitting results indicated a higher correlation coefficient of 0.9588 for hydrogel in 1:2 [or M4(Cu2+)] mole ratio of feed composition adsorption in both Langmuir and Freundlich isotherms. The evaluation of adsorption kinetics indicated a strong fit of the pseudo-first-order Elovich model, evidenced by correlation coefficients of 0.9685 and 0.9186 for Cu2+ and Pb2+ adsorption, respectively.

In our study, we developed a novel magnetic-solid-phase extraction (mag-SPE) sorbent by using NiFe2O4 nanoparticles (NPs) as a magnetic core, with HKUST-1 serving as the metal-organic framework (MOF) shell. Sorbent was fabricated using the Pechini method and characterized and confirmed through various techniques. Following characterization, the synthesized mag-SPE sorbent was combined with Flame Atomic Absorption Spectroscopy (FAAS) to determine and quantify heavy metals (Pb, Cd, and Hg) in various cosmetic product samples available in the Iranian market. We studied the effect of various variables to determine the optimal extraction conditions. The concentration was assessed over a linear range under these optimized conditions: 0.5-1700 µg L−1 for Pb, 1-1500 µg L−1 for Cd, and 1-2000 µg L−1 for Hg. The R2 values were 0.99992, 0.99746, and 0.99547, respectively. The LOD (signal (S) to noise (N) = 3) and LOQ (S/N=10) for Pb were 0.147 µg L−1 and 0.492 µg L−1, for Cd they were 0.162 µg L−1 and 0.541 µg L−1, and for Hg they were 0.294 µg L−1 and 0.981 µg L−1. Moreover, the relative standard deviation (RSD) for Pb, Cd, and Hg were 1.24%, 1.22%, and 1.15%, respectively. Finally, we used the mag-SPE-FAAS method to measure the levels of Pb, Hg, and Cd in various cosmetic samples, including 8 foreign and 7 domestic brands of lipsticks, eye shadows, and hair colors. The results were then analyzed separately for each cosmetic sample and compared between the foreign and domestic brands.

The study focuses on the synthesis of nanocomposite adsorbents from modified Graphene Oxide (mGO) polymerized with 5-AIPA groups (mGO-AIPA) using a simple coprecipitation method. Various methods including FT-IR, TGA, FESEM, XRD, and VSM were utilized to assess the morphology and properties of nanoparticles. The study analyzed the effectiveness of Cd (II) and Pb (II) ion adsorption by using the composite Response Surface Method (RSM). The factors evaluated included adsorbent dose, pH, contact time, and initial ion concentration. The results showed that the mGO-AIPA nanocomposite had the highest adsorption capacity for Cd (II) ions, at 120.51 mg/g, and for Pb (II) ions, at 198.79 mg/g, both at a pH level of 6.5. The correlation coefficients for the adsorption of Pb (II) and Cd (II) ions in the Freundlich isotherm model were 97% and 95%, respectively. Moreover, the removal of both metal ions by the mGO-AIPA nanocomposite was consistent with the 97% correlation coefficient of the pseudo-second-order kinetic model. The thermodynamic model analysis indicated that the adsorption process of both metals by the mGO-AIPA nanocomposite was exothermic and spontaneous. In conclusion, the study suggests that magnetic graphene oxide functionalized with organic polymers is an effective method of eliminating heavy metal pollution, particularly cadmium and lead ions, from aquatic environments.

Heavy metals such as cadmium and lead have profound effects on the immune system, causing both overstimulation and suppression of immune responses. This dysregulation leads to immune dysfunction and increases the risk of adverse inflammatory outcomes. Disruption of immune regulation can result in chronic inflammation, requiring a detailed understanding to develop effective therapeutic strategies. The aim of the present study was to investigate the effects of cadmium chloride (CdСl2) and lead acetate (Pb(CH3COO)2) on the course of aseptic inflammation (SI), as well as the possibility of immune modulation of the identified disorders. The study was conducted on 4 groups of animals, with 42 outbred male rats weighing 180-220 g (±20 g), kept under standard vivarium conditions on a regular diet. Experimental animals were intoxicated with 2.5 mg/kg doses of Cd and Pb orally for two weeks, after which aseptic inflammation was modeled in the animals. In this work, we investigated the activity of CD4+, CD4+CD25+ (activated T cells), CD4+FoxP3+, CD4+FoxP3+CTLA-4+, CD45R(B220), RT1+ from the CD45+CD45R(B220) + population using flow cytometry; IL-6, TGFβ using enzyme-linked immunosorbent assay (ELISA); and hematological blood analysis. It was found that cadmium and lead salts cause immune system dysfunction, leading to dysregulation of inflammation and increasing the risk of adverse outcomes. Treatment with Complex demonstrated potential in restoring the balance of effector and regulatory lymphocytes. Complex, after 7 days, through activation of IL-6 and TGF-β, restored splenic CD4+ lymphocyte populations, selectively stimulated FoxP3+ expression, but did not affect the suppressive activity of CTLA-4+. Complex also activated innate and adaptive immunity, enhancing the antigen-presenting activity of macrophages and stimulating leukocyte reactions, which is especially important for a favorable outcome of the inflammatory process against the background of heavy metal intoxication.

Biopolymers are characterized by their three-dimensional polymeric networks, high hydrophilic properties, affordability, physical and chemical stability, non-toxicity, and exceptional ability to absorb water and other substances. In this work, the adsorption capacity of an inexpensive, biodegradable adsorbent, poly (AAC-co-AM) hydrogel, prepared by the free radical polymerization method, was studied for the removal of heavy metals such as Fe (II) ions. Several analyses of the hydrogel were performed, including FESEM, TEM, and XRD. The effects of various conditions on the adsorption process were investigated, such as hydrogel weight, Fe (II) ion concentration, equilibrium time, and adsorption isotherms. Iron ion adsorption increased from 77.25% to 97.91% as the weight of the hydrogel increased from 0.01 to 0.1 g/50 mL. However, the adsorption capacity decreased from 29.14 to 233.33 mg/g at a fixed Fe (II) ion concentration of 30 mg/L, an equilibrium time of 1 hour, the temperature of 25 °C, and a stirring speed of 150 rpm. As the equilibrium time increased, both the adsorption efficiency and removal percentage rose. In addition, increasing the weight of the poly (AAC-co-AM) hydrogel led to an increase in the removal percentage. The results revealed that the adsorption efficiency of poly (AAC-co-AM) hydrogel was 55.62 mg/g with a removal percentage of 92.78% at pH 7, a dose of 0.1 g/50 mL, an equilibrium time of 1 hour, an Fe (II) ion concentration of 30 mg/L, and the temperature of 25 °C. Beyond this, the adsorption efficiency began to decrease. Finally, the adsorption equilibrium was studied using the Langmuir and Freundlich isotherms. The data were best described by the Freundlich model.

The increasing contamination of water by various heavy metals has emerged as a pressing global issue, threatening human health, aquatic ecosystems, and agricultural sustainability. These heavy metals are required to remove through cost effective and efficient removal approaches due to their toxicity, persistence and bioaccumulation. This review explores the transformative potential of nanocomposites as advanced adsorbents for heavy metal elimination. By investigating their synthesis, characterization, and functional classifications, the study highlights how these materials outperform conventional methods through enhanced surface properties and adsorption efficiency. A comparative analysis of adsorption mechanisms, such as ion exchange, electrostatic interactions, and complexation, is addressed, alongside evaluations of critical operational parameters like pH, contact time, and percentage removal. Additionally, the paper also outlines the limitations of current nanocomposite technologies, such as scalability challenges and environmental concerns, while potential future options for the removal of heavy metals. This review sets the groundwork for future nanomaterials developed to address global water decontamination by extending knowledge in this field.

The pollution of aquatic ecosystems by heavy metals poses a significant and immediate environmental threat worldwide. Industrial operations often result in the direct discharge of effluents into rivers, lakes, and ponds, leading to the contamination of these water bodies. Subsequently, these pollutants can percolate into groundwater systems through a range of transport mechanisms. Although certain heavy metals play essential roles in the metabolic processes of organisms, their elevated concentrations in aquatic environments present substantial risks, disrupting ecological balance and potentially affecting human health. This study examines the process of copper (Cu) removal from wastewater using electrocoagulation techniques. The research found that the effectiveness of copper extraction increased with extended electrocoagulation times, higher concentrations of sodium chloride (NaCl), and elevated applied electric currents. The most efficient removal was achieved under optimal conditions, which is defined as an average pH level of about 4 and a current of 2 A , and a duration of electrolysis set at 60 minutes.

The quantitative structure-property relationship (QSPR) method is an efficient and elegant method for estimating the critical parameters of a wide range of compounds. In this work, the QSPR data set included the structures of 45 modified diphenyl phosphoryl acetamide ionophores along with their sensitivity to Cd2+, Cu2+, and Pb2+. The data set was divided into the training set, including 36 compounds, and the test set, including 9 compounds. The stepwise -multiple linear regressions (SW-MLR), firefly multiple linear regressions (FA-MLR), and firefly-support vector machine (FA-SVM) models were produced on the training set with sensitivity of ionophores for Cd2+, Cu2+, and Pb2+ for predicting the potentiometric sensitivity of plastic polymer membrane sensors. The FA-SVM model showed good statistical results for all three cations. Internal and external validation was done to ensure the performance of the model. The results showed acceptable accuracy of the proposed method in identifying important descriptors in QSPR. The results of this study and the interpretation of the descriptors entered in the model can help to design new selective ligands.

The removal of heavy metal ions (Cr, Pb, and Zn) present in aqueous solutions has been examined using Sargassum Wight (SW) - brown algae – as an organic adsorbent. The functional groups of SW were determined by FT-IR analysis before and after heavy metal ion adsorption. Because of the strong Van der Walls forces, the SEM/EDX picture reveals the presence of heavy metal ions on the surface of the SW. The influence of adsorption was studied in different settings by adjusting the parameters of pH, SW dosage, metal ion concentration, time of contact, and temperature. In addition, thermodynamic and isotherm investigations were carried out in order to determine the adsorption process and its connection. It was found that by adding 0.3 N H2SO4, the maximal desorption rate was achieved. Around 99.6% of chromium ions, 89.27% of lead ions, and 82.39% of zinc ions were removed from the synthetic solutions through batch-mode adsorption studies.

Most cosmetic products contain heavy metals. These metals are toxic and can accumulate in the body over time, causing various health effects to human health. This study aims to assess the concentrations of five heavy metals (lead, chromium, cadmium, iron and nickel) in some facial cosmetic products (foundation cream, lipstick, and mascara), collected from Benghazi cosmetic shops. Eighteen of facial cosmetic products were randomly collected from cosmetic shops. The samples were digested and analysed using Flame Atomic Absorption Spectrophotmeter. Furthermore, the non-carcinogenic and carcinogenic risk assessments were evaluated by calculating the hazard quotient (HQ) and hazard index (HI) of heavy metals in the analysed makeups.  The highest mean concentrations of chromium, nickel, lead and cadmium were detected at 0.39±0.1mg/kg, 2.88±1.8mg/kg, 1.85±0.4mg/kg and 0.31±0.06mg/kg, respectively, in foundation cream samples. While the highest mean concentration of iron was detected at 117.80±22.0mg/kg in lipstick samples. The ANOVA test revealed a significant difference in the concentrations of analysed metals among the three brands of facial cosmetic products, except for chromium, nickel iron and lead metals, in mascara and lipstick products. The HQs of all metals in the selected cosmetics were <1. Also, the HI value was <1. The results of the current study demonstrated that the concentrations of the heavy metals in the cosmetic samples were within the permissible limits set by different international organizations. The risk assessment study indicated that the cosmetics were relatively safe with minimal health risks.

Carbon dots (CDs) have garnered significant attention in heavy metal (HM) sensing due to their exceptional optical properties and numerous advantages. Due to the rapid industrialization in the last couple of decades, the accumulation of HM in the environment poses a major threat to humans and marine and terrestrial organisms in the Indian subcontinent. Therefore, the detection of HM in the environment is of paramount importance. This review delineates the latest progress in employing CDs for heavy metal detection, specifically focusing on those with dual-emissive fluorescence characteristics, highlighting their superiority compared to traditional detection approaches. Additionally, eco-friendly synthesis methods and the mechanisms through which heavy metals are sensed by CDs are investigated, with emphasis placed on their benefits, such as high sensitivity and selectivity in metal detection applications. The review examines a variety of detection methods employing CDs, such as fluorescence, colorimetry, electrochemical techniques sensing, and ratiometric fluorescence methods, and elucidates their distinct applications. Furthermore, it focuses on approaches aimed at enhancing the sensing capabilities of CDs through surface functionalization, doping, and composite formation. By providing a comprehensive overview of detection methods and suggesting avenues for further research and development, it aims to contribute to the advancement of this field.

This research investigated heavy metals content and their potential health problems in some rivers across Nasarawa west, Nigeria. The mean concentration of Zn was recorded as 0.32 mg/L which was lower than the limits set by the World Health Organization (WHO), USEPA, and EU. Cu with mean of 0.03 mg/L was also lower than limits set by the WHO, USEPA, and EU. Fe with mean of 1.25 mg/L are found higher than limits prescribed by the WHO, USEPA, and EU. Cd with mean of 0.01 mg/L are lower than limits set by the WHO, USEPA, and EU. Pb with mean of 0.01 mg/L are lower than limits set by the WHO, USEPA, and EU. Lastly as with mean of 0.01 mg/L are equal to limits set by the WHO, USEPA, and EU. The values for validation parameters are low indicating minimal variability and uncertainty in our measurements, signifying high precision in measuring instruments and the tested samples. The pH measurement of all the samples proved acidic. Based on the elevated values of iron (Fe) and arsenic (As) recorded in this study, regular monitoring and treatment of drinking water sources are essential to ensure compliance with regulatory limits and to provide iron and arsenic-free as well as other metal-free drinking water to the public within the investigated location.

Water is not only essential for life, but also it is life. Safeguarding this resource from heavy metals is good for our well-being. This research investigated heavy metals content and their potential health problems in some rivers across Anambra, Nigeria. The mean concentration of Zn was recorded as 0.03 mg/L which was lower than the limits set by the World Helth Organization (WHO) (3 mg/L), USEPA (5 mg/L), and EU (3 mg/L). Cu (0.003 mg/L) was also lower than limits set by the WHO (2 mg/L), USEPA (1.3 mg/L), and EU (2 mg/L). Fe (1.177 mg/L) was found higher than limits prescribed by the WHO (0.3 mg/L), USEPA (0.3 mg/L), and EU (0.2 mg/L). Cd (0.001 mg/L) was lower than limits set by the WHO (0.003 mg/L), USEPA (0.005 mg/L), and EU (0.005 mg/L). Pb (0.001 mg/L) was lower than limits set by the WHO (0.01 mg/L), USEPA (0.015 mg/L), and EU (0.01 mg/L). Lastly, As (0.01 mg/L) was equal to limits set by the WHO (0.01 mg/L), USEPA (0.01 mg/L), and EU (0.01 mg/L). The values for validation parameters are low indicating minimal variability and uncertainty in our measurements, signifying high precision in measuring instruments and the tested samples. The pH measurement of all the samples proved acidic. Based on the elevated values of iron (Fe) and arsenic (As) recorded in this study, regular monitoring and treatment of drinking water sources are essential to ensure compliance with regulatory limits and to provide iron and arsenic-free as well as the other metal-free drinking water to the public within the investigated location.