Removal Of Inorganic Pollutants Research Articles

Polycaprolactone-zinc oxide biocomposite membranes for wastewater treatment by ultrafiltration process: Synthesis, characterization and removal of inorganic pollutants

The severe droughts impacting North Africa have intensified the pressure on potable water supplies and agricultural irrigation, highlighting the urgent need for sustainable water management solutions. This study explores the potential of poly(ε-caprolactone)/zinc oxide (PCL/ZnO) biocomposites as ultrafiltration membranes for treating urban wastewater, with the goal of enabling water reuse in agriculture. PCL/ZnO membranes, fabricated using the solvent-casting method, were thoroughly characterized using FTIR, XRD, EDAX, SEM, AFM, DSC, TGA, and water contact angle (WCA) measurements. Key findings revealed that increasing ZnO content (1–4 wt%) significantly enhanced membrane thickness, crystallinity, mechanical robustness, and surface roughness, while lowering WCA values to improve hydrophilicity. These enhanced properties are critical for ultrafiltration, as they contribute to higher contaminant rejection and improved water permeability. Performance tests demonstrated ion retention rates of 32–61 % post-filtration, including for toxic metals, effectively reducing pollutant levels. Notably, the treated water met the Food and Agriculture Organization (FAO) standards for irrigation quality, indicating its suitability for agricultural applications. This work highlights the efficacy of PCL/ZnO membranes in facilitating sustainable wastewater recycling under drought conditions, presenting a promising, adaptable solution for water reclamation in water-scarce regions. The results underscore the potential of these biocomposite membranes to advance sustainable water treatment practices, supporting both environmental resilience and agricultural productivity.

Removal of Inorganic Pollutants and Recovery of Nutrients from Wastewater Using Electrocoagulation: A Review

Water pollution is a major concern due to its detrimental effects on the environment and public health. The particular danger of inorganic pollutants arises from their persistent toxicity and inability to biodegrade. Recently, electrocoagulation (EC) has been demonstrated as an alternative sustainable approach to purifying wastewater due to the increasingly strict pollution prevention rules. In particular, EC has been used to remove inorganic pollutants, such as Cr, Zn, Pb, or As. EC has emerged as a sustainable tool for resource recovery of some inorganic pollutants such as N and P that, when recovered, have value as plant nutrients and are critical in a circular economy. These recovered materials can be obtained from diverse agricultural drainage water and recycled as fertilizers. In this work, a state-of-the-art technique is reviewed describing the advances in contaminant removal and nutrient recovery using EC through an in-depth discussion of the factors influencing the contaminant removal process, including operating pH, time, power, and concentration. Furthermore, limitations of the EC technology are reviewed, including the high-power consumption, fast deterioration of the sacrificial electrodes, and the types of contaminants that could not be efficiently removed. Finally, new emerging constructs in EC process optimization parameters are presented.

Acid mine drainage treatment and metals recovery by means of selective precipitation using magnesium oxide (MgO): An experimental study

The treatment of acid mine drainage (AMD) by metals precipitation and neutralization releases a huge volume of highly polluted toxic sludge which can be valorized by the recovering of chemical species. In this study, the treatment of AMD and chemical species recovery by means of selective precipitation using magnesium oxide (MgO) was explored. One litre and half (1500 mL) of AMD from coal mine was used for the experiment. The pH of AMD water was gradually increased using an overhead stirrer and chemical species recovered at different pH gradients via a sequential precipitation technique. The results revealed that Fe(III) was recovered at pH 2.9–4 interval, Al at pH ≥ 4, Cu at pH ≥ 6.5, gypsum at pH 2.9–9.5 interval, Fe(II) at pH ≥ 7.5, Mn, Ni and Zn pH ≥ 8. The results further revealed significant removal of inorganic pollutants in the following order: Cu (100%) = Ni (100%) ≥ Fe (99.9%) ≥ Al (99%) ≥ Mn (98.6%) ≥ Zn (97.2%) ≥ SO42─ (76%). Reduction of electrical conductivity (EC) and total dissolved solid (TDS) were also observed in the order of 82% and 85% respectively. Characterization studies were used to underpin and succinct the fate of chemical species of pure MgO and sludge recovered at different pH gradients. The product water obtained at pH 9.5 conformed to the prescribed standard for effluent discharge as prescribed by regulatory bodies.

Organic and inorganic pollutants removal from tannery effluent using electrocoagulation technique

Abstract Electrocoagulation is an efficient treatment for the concurrent elimination organic and inorganic contaminants from tannery wastewater. The batch electrocoagulation investigations were carried out using mild steel and aluminium as sacrificial anodes and stainless steel as the cathode. Various operating constraints, such as the electrolyte pH, realistic current density, electrolysis time, effluent concentration and supporting electrolyte concentration were appraised to study their effects on electro-coagulation efficiency. The maximum Total Organic Carbon (TOC) removal has been observed was 90 % and 77 % under optimum operating conditions, and the maximum chromium removal has been recorded was 99 % and 90 % using mild steel and aluminium anodes respectively. The experimental data was also fitted with the first order kinetic model. The experimental data were investigated with the Langmuir and Freundlich adsorption isotherm models. The result shows that the experimental data fitted with the Langmuir isotherm model, with a rate of confidence of 0.98, using mild steel as an anode. The solid sludge and the liquid samples were characterized using the SEM (scanning electron microscopy) EDX (energy dispersive X-ray spectrometry), FT-IR (Fourier transform infrared spectrometer) and UV–Visible (Ultraviolet–visible spectroscopy) analyses. All experimental results show that mild steel was an efficient anode, for the instantaneous elimination of organic and inorganic contaminants from tannery wastewater.

Removal of Inorganic Pollutants from Wastewater: Innovative Technologies and Toxicity Assessment

In the past decade, a sudden increase in the number and kind of emerging water contaminants has been observed. The emerging contaminants can be categorized as organic or inorganic. Organic contaminants have been known for years, and techniques for their detection and remediation have been developed. However, inorganic pollutants are much more common. This is because they are detected in very low or negligible concentrations and are equally toxic as organic pollutants at higher concentrations. To boost the research on inorganic pollutant contamination, advancements in detection and quantification techniques are required. The presented paper discusses major inorganic pollutants such as metals and their salts, inorganic fertilizers, sulfides, acids and bases, and ammonia and oxides of nitrogen. In addition, it discusses the inorganic toxicants’ toxicity to organisms and the environment, upgraded quantification methods, and advancements in inorganic toxicant mitigation. Moreover, the major bottlenecks in the quantification and removal of inorganic pollutants are discussed at the end.

Ferrite-Supported Nanocomposite Polymers for Emerging Organic and Inorganic Pollutants Removal from Wastewater: A Review

Ferrite-Supported Nanocomposite Polymers for Emerging Organic and Inorganic Pollutants Removal from Wastewater: A Review

Evaluation of the Biosorption Performance of Marine Green Algae Biomass (Ulva lactuca sp.) in the Removal of Inorganic Pollutants

Evaluation of the Biosorption Performance of Marine Green Algae Biomass (Ulva lactuca sp.) in the Removal of Inorganic Pollutants

One-step solvothermal synthesis of the bimetallic Zr/Ce-UiO-67 metal–organic framework: a visible-light-activated photocatalyst for Cr(vi) detoxification

The Zr/Ce-UiO-67 photocatalyst is used for the efficient removal of inorganic pollutants through exposure to visible-light irradiation.

Transient absorption spectroscopy insights into heterogeneous photocatalysis for water pollution remediation

Transient absorption studies have contributed to our current understanding of heterogeneous photocatalytic systems. Insights have been gained into the nature of the photogenerated charge carriers and their trapping, their subsequent transfer to the reaction medium, the transformations and kinetics that ensue from transient species to the final reaction products, and equally important the time scales at which these events occur. In this review, the focus is on learnings relevant to heterogeneous photocatalytic systems for water pollution remediation. It is subdivided into sections on TAS studies of heterogeneous photocatalysis for: Dye degradation (Section 2.0); Organic pollutant degradation (Section 3.0); and Inorganic pollutants removal (Section 4.0). The majority of the studies has been on heterogenous TiO2 photocatalysis, but more recently novel photocatalytic materials such as doped and heterostructured materials have also been studied. Those latter systems have great potential for the development of solar driven heterogeneous photocatalysis for environmental remediation.

Construction of Zeolite/Fe2ZnTiO6/graphene oxide multifunctional nanocomposite with high efficiency for photocatalytic removal of inorganic pollutants under visible irradiation

Nowadays, pollutants of toxic heavy metals (THMs), nitrate (NO3-), and carbon dioxide (CO2) are three types of important environmental pollutants that have become a global concern. In recent years, perovskite photocatalysts have created great development prospects in pollutants treatment of aqueous solutions, industrial wastewaters, and air. Herein, Zeolite/Fe2ZnTiO6 (FZTO) double perovskite/graphene oxide (GO) nanocomposite (NC) was prepared as a highly efficient multifunctional perovskite photocatalyst by the sol-gel method. The crystal structure, morphology, and composition of the synthesized nanocomposite were characterized by XRD, SEM, and EDX-Map analysis. Also, photocatalytic mechanisms of the Zeolite/Fe2ZnTiO6/graphene oxide nanocomposite were evaluated by PL, DRS, and UV–visible analysis. Photocatalytic activity of Zeolite/Fe2ZnTiO6/graphene oxide nanocomposite was evaluated for the removal of toxic heavy metals, nitrate, and carbon dioxide pollutants in experiment conditions including pH (1–9), the temperature (25–65 °C), stirring speed (100–500 rpm), retention time (1–6 h), photocatalyst dosage (0.25–1.5 g/l), pollutants concentration (5–120 mg L−1) and distance between the visible source and solution surface (5–20 cm). The UV–visible spectrums were shown the removal efficiency of 90% for toxic heavy metals in optimal conditions of pH;7, temperature; 25 °C, stirring speed; 200 rpm, retention time; 5h, photocatalyst dosage; 1 g/l, THMs concentration; 10 mg L−1, and distance between the light source and solution surface; 10 cm under visible light irradiation. Also, the highest degradation efficiency of NO3− pollutant from aqueous solution was determined at about 85% in optimized conditions of pH; 3, temperature; 25 °C, agitation rate; 200 rpm, reaction time; 5h, photocatalyst dosage; 1 g/l, NO3−concentration; 100 mg L−1, and distance between the surface of the solution and light source; 10 cm under visible light irradiation. Finally, conversion maximum of CO2 pollutant was obtained at about 80% in optimum conditions of pH; 3, temperature; 25 °C, mixing rate; 200 rpm, retention time; 5h, photocatalyst dosage; 1 g/l, CO2 concentration; 100 mg L−1, and distance between the solution surface and light source; 10 cm under visible light irradiation.

Co-over expression of Ascorbate Glutathione pathway enzymes improve mercury tolerance in tomato

The genetic modification of plants for the removal of inorganic pollutants from contaminated soil and water bodies is an emerging area for addressing environmental concerns. This approach is based on the ability of plants to take up and accumulate heavy metals, with efficiency being dependent on the underlying mechanisms of heavy metal accumulation and tolerance. A robust antioxidant pathway is determinantal for heavy metal uptake and accumulation and, therefore, in this study, we evaluated the transgenic tomato plants installed with Ascorbate Glutathione (ASA-GSH) pathway genes for uptake, accumulation, and response to mercury (Hg). We observed that ASA-GSH overexpressing lines were resilient to Hg stress as they displayed higher photosynthetic activity and increased photosynthetic gas exchange parameters with a concomitant decrease in ion leakage under Hg stress. Additionally, transgenic lines accumulated high osmolytes and showed enhanced activity of antioxidant enzymes. Moreover, the results of SEM and confocal microscopy confirmed least damage to plant tissue in ASA-GSH overexpressing lines compared to wild-type under Hg-stress which was further supported by Atomic absorption study that revealed a significant decline in Hg accumulation in the leaves of transgenic lines compared to wild-type under stress conditions. In conclusion, pyramiding of ASA-GSH pathway genes in tomato plants is an efficient approach for the development of Hg-resistant tomato plants and the reclamation of Hg-contaminated sites.

In situ Functionalized Mesoporous Silicas for Sustainable Remediation Strategies in Removal of Inorganic Pollutants from Contaminated Environmental Water.

Low-cost mesoporous silicas of the SBA-15 family were prepared, aimed for removal of a broad spectrum of both cationic and anionic forms of hazardous metal pollutants (Cr(III, VI), Mn(II, VII), Pb(II), Cd(II), and Cu(II)) from environmental water. Series of mono- and bifunctional materials with immobilized ethylenediaminetriacetic acid (EDTA), primary amine (NH2), and quaternary ammonium (QAS) groups were prepared in a cost-efficient one-step synthesis using two silica sources, low-cost sodium metasilicate (Na2SiO3 9H2O) and the conventional source—tetraethylorthosilicate (TEOS). The functionalized SBA-15 samples obtained from both silica sources were highly ordered, as evidenced by TEM and SAXS data. All obtained materials were mesoporous with high surface area values of up to 745 m2/g, pore volumes from 0.99 to 1.44 cm3/g, and narrow pore distributions near 7 nm. The adsorption affinity of the EDTA-functionalized samples followed the common order Pb(II)> Cd(II)> Cu(II)> Cr(III)> Mn(II), which could be explained based on the Pearson theory. The highest adsorption capacities were observed for samples functionalized by EDTA groups using TEOS for synthesis (TEOS/EDTA): 195.6 mg/g for Pb(II), 111.2 mg/g for Cd(II), 58.7 mg/g for Cu(II), 57.7 mg/g for Cr(III), and 49.4 mg/g for Mn(II). Moreover, organic matter (humic acid up to 10 mg/L) and inorganic (Na(I), K(I), Mg(II), Ca(II), etc) macrocomponents present in environmental water had almost negligible effect on the removal of these cations. The NaSi/EDTA/NH2 sample revealed a better selectivity compared to the NaSi/NH2 sample towards such species as Cr(III), Mn(II), Cd(II), and Cu(II). The chromate-ions uptake at pH 7.5 by the TEOS/QAS sample turned practically unaffected by the presence of doubly charged anions (CO32–, SO42–). The content of functional groups on the surface of MS decreased only slightly (∼1–5%) after several regeneration cycles. The complete desorption of all heavy metal ions can be achieved using 1 mol/L EDTA solution. Reusability tests demonstrated the complete stability of the adsorbent for at least five to six consecutive adsorption/desorption cycles with no decrease in its adsorption characteristics compared to those obtained by 0.05 mol/L HNO3 treatments. The synthesized mesoporous materials were evaluated for removal of the heavy metal ions from drinking and different natural water samples, proving their potential as sustainable, effective, and cost-efficient adsorbents.

Enhanced Electroremediation of Metals from Dredged Marine Sediment under Periodic Voltage Using EDDS and Citric Acid

The electrokinetic remediation (EKR) method has been extensively considered for the removal of inorganic pollutants from contaminated dredged sediment. In addition, the use of chelating agents as electrolyte solutions has been beneficial in increasing the mobility of metals. This study investigated the metals’ (Cd, Cr, Cu, Pb, and Zn) mobilities by assessing the effect of two environmentally friendly chelating agents, ethylenediaminedisuccinic acid (EDDS) and citric acid (CA), in enhancing the EKR efficiency under a periodic voltage gradient. The results showed that, for the same concentration (0.1 mol L−1), CA is more suitable for enhancing the removal of Cr (67.83%), Cu (59.77%), and Pb (32.05%) by chelating and desorbing them from the sediment matrix and concentrating them in the electrode compartments. EDDS provided efficiency to improve the Cd extraction percentage (45.87%), whereas CA and EDDS had comparable improvement removal impacts on Zn EKR (39.32% and 41.37%, respectively). From the comparison with previous results obtained with a continuous voltage, applying a periodic voltage gradient associated with a low concentration of chelating agents led to a promising result.

Photocatalytic activity of CuO nanoparticles for organic and inorganic pollutants removal in wastewater remediation

Heterogeneous photocatalysis is a promising technology for eradicating organic, inorganic, and microbial pollutants in water and wastewater remediation. It is a more preferable method to other conventional wastewater treatment approaches on account of its low cost, environmental benignity, ability to proceed at ambient temperature and pressure conditions, and capability to completely degrade pollutants under appropriate conditions into environmentally safe products. In heterogeneous photocatalysis, pollutant removal is mainly induced by in-situ generated reactive radicals and their subsequent attack when energetic radiation impinges on the semiconductor catalyst. As such, for the effective and economical removal of wastewater pollutants, the employed catalyst should have high photonic efficiency, less toxic, abundant, chemically and photochemically stableand visible light active. Copper (II) oxide (CuO) is one among such promising compounds and its photocatalytic performance has been hampered primarily by rapid recombination and slow mobility of photogenerated charge carriers. So, this review provides an overview of the strategies adopted to mitigate the aforementioned drawbacks and also other operational parameters to boost its catalytic activity towards the elimination of toxic organic and inorganic metal ion contaminants in an aqueous media.

An Evaluation of the Activity of Prepared Zinc Nanoparticles with Extracted Alfalfa Plant in the Treatment of Heavy Metals

The alfalfa plant, after harvesting, was washed, dried, and grinded to get fine powder used in water treatment. We used the alfalfa plant with ethanol to make the alcoholic extract characterized by using (GC-Mass, FTIR, and UV) spectroscopy to determine active compounds. Alcoholic extract was used to prepare zinc nanoparticles. We characterized Zinc nanoparticles using (FTIR, UV, SEM, EDX Zeta potential, XRD, AFM). Zinc nanoparticle with Alfalfa extract and alfalfa powder were used in the treatment of water polluted with inorganic elements such as Cr, Mn, Fe, Cu, Cd, Ag by (Batch processing). The batch process with using alfalfa powder gets treated with Pb (51.45%), which is the highest percentage of treatment. Mn (13.18%), which is the lowest percentage of treatment. The batch process with using Zinc nanoparticles gets the result treated with Pb(98.822%), which is the highest percentage of treatment, and Mn (10.31%), which is the lowest percentage of treatment. When comparing alfalfa powder and zinc nanoparticle, it has been found that the treatment with zinc nanoparticle is more efficient in the removal of inorganic pollutants.

Functional activated carbon: from synthesis to groundwater fluoride removal.

Developing green and functional adsorbents for the removal of inorganic pollutants from industrial wastewater is still a great challenge. Activated carbons (ACs) are promising eco-friendly materials for adsorption applications. This study reports on the preparation and functionalization of AC and its application for fluoride removal from water. Activated carbon was prepared from date stems, and the material was employed as a support for different modifications such as incorporation of Al(OH)3, in situ dispersion of aluminum particles (Al0) and grafting of 3-(aminopropyl)triethoxysilane (APTES). The resulting functional adsorbents were fully characterized by Fourier transform infrared spectroscopy, scanning electronic microscopy, energy dispersive X-ray fluorescence, X-ray diffraction, differential scanning calorimetry and zeta potential analysis. The results evidenced successful surface modifications. All adsorbents had affinity for the removal of fluoride ions (F−). The highest F− removal rate was up to 20 mg g−1 for AC-Al(OH)3. Removal of fluoride ions obeyed Langmuir isotherms and a second-order kinetic model, and reached 99% uptake. The AC-Al(OH)3 adsorbent was successfully used to treat a groundwater solution contaminated by fluoride ions. These results open an interesting avenue for developing eco-friendly functionalized AC for adsorption applications.

Fabrication of tunable oxygen vacancies on BiOCl modified by spiral carbon fiber for highly efficient photocatalytic detoxification of typical pollutants

Flower-like spiral carbon fiber (SCF)/BiOCl composite photocatalysts with adjustable oxygen vacancies (OVs) were successfully fabricated via SCF surface modification of BiOCl. The sample composition and the photogenerated carrier separation efficiency were tested by various characterization methods. Compared with BiOCl, SCF/BiOCl photocatalysts display higher level of OVs and produce more superoxide radicals. The presence of OVs leads to the formation of an impurity energy level between the energy band of BiOCl. In addition, the SCF can transfer some of the photogenerated electrons produced by BiOCl. With the synergistic effect of OVs and SCF, an effective separation of photogenerated carriers is achieved. Photocatalytic activity of the samples was evaluated by the removal of inorganic pollutants (Cr (VI)) and organic pollutants (phenol and Tetracycline (TC)). The activity results show that SCF/BOC-1.75 for TC, phenol and Cr (VI) is 3.2, 2.5 and 10.6 times of that of the neat BOC; 0.9, 1.8 and 4.9 times of that of P25 under simulated sunlight illumination, respectively. The primary active species in the reaction system were investigated and the reaction mechanism was deduced.

Synthesis of biogas-residue-based mesoporous carbons via one-step template-free method for organic and inorganic pollutants removal

Biogas-residue-based mesoporous carbons with high adsorption capacity have been successfully synthesized via a facile template-free and one-step approach by sodium amide activation and applied in the removal of organic and inorganic pollutants in wastewater for the first time in this study. A “waste” and widely available resource, biogas residue, was utilized as carbon precursor. Different mesoporous carbons were prepared by direct co-milling and activation at various conditions, among which largest surface area of 1278 m2/g and maximum adsorption of 556 mg/g on methylene blue were achieved, respectively. It is also verified to possess superior adsorption capacity on typical organic pollutant phenanthrene (112 mg/g) and typical inorganic pollutant N/P element (N, 113 mg/g; P, 12 mg/g). The results show that the prepared mesoporous carbons possess high and universal adsorption performance toward both organic and inorganic pollutants in wastewater. Finally, the adsorption mechanism such as the relationship between the adsorption capacities and characterization results was also discussed. The low-valued raw materials, convenient procedure, energy conservation, minimum pollution and corrosion, high adsorption capacity show feasible manufacture in industry.

Direct Z-scheme of WO3/GO decorated with silver nanoparticles for synergetic adsorption and photocatalytic activity for organic and inorganic water pollutants removal

Synergism between adsorption and photocatalytic activity in heterocatalysis improve the overall performance of organic and inorganic pollutants removal. We report the WO3/GO composite immobilized on chitosan to enhance the adsorption process and decorated with Ag NPs for efficient photocatalytic visible light absorption. The ternary photocatalyst (x%Ag/WO3/GO (x = 0, 1, and 3) was characterized by SEM, TEM, XRD, FTIR, XPS, and UV–Vis techniques. The obtained results show that both GO sheets and CS enhanced the adsorption process, while Ag NPs enhance the photocatalytic performance of WO3/GO composite. As expected, the 3 %Ag/WO3/GO shows excellent catalytic and photocatalytic performance of the removal of organic (methylene blue, and p-nitrophenol) and inorganic (Cr6+) water pollutants. 3 %Ag/WO3/GO composite removes 98% of MB (20 min) in absence of light, where more than 98% of MB (8 min) and 95% of p-nitrophenol (8 min) were removed after visible light irradiation. Enhanced adsorption of MB and Cr6+ was attributed to π-π stacking and electrostatic attractive potential over the catalyst, respectively. Based on the experimental results and trapping experiments, the charge separation through the Z-scheme WO3/GO facilitate the charge migration and boost the photocatalyst performance.

Biochar derived from Salvadora persica branches biomass as low-cost adsorbent for removal of uranium(VI) and thorium(IV) from water

In recent years, biochar based adsorbents have been given more attention for organic and inorganic pollutants removal. Therefore, in this study, a new low-cost biochar adsorbent derived from Salvadora persica branches (BSP) was prepared, characterized and investigated for removal of U(VI) and Th(IV) radioactive elements from water. The effects of batch adsorption conditions were studied. The maximum removal efficiencies are around 99% for each of U(VI) and Th(IV), with adsorption capacities 85.71 mg g−1 and 84.97 mg g−1 respectively. It has been found the adsorption process of U(VI) and Th(IV) is spontaneous, exothermic and follows pseudo-second-order kinetics.