Elimination Of Heavy Metals Research Articles

Synthesis of Dispersed Magnetic Fe3O4 Nanohydrogel Based on Gelatine by Gamma Irradiation for Toxic Heavy Metals Removal

AbstractHeavy metals are among the problematic groups of contaminants. They are discharged from various industries. The wastewater disposed by heavy metals is causing major hazards to the environment. Different hydrogels based on Gelatin (gelt/AAm/EDTA) and nano- (Fe3O4/gelt/AAm/EDTA) were prepared by gamma radiation at 60 KGy and employed for heavy metals elimination. The structure and surface morphology of the manufactured hydrogels were confirmed with FTIR, X-ray, surface area, and SEM. The prepared hydrogels were characterized in terms of their gel content. The swelling properties were studied as a function of time. This research aims to investigate the adsorption properties of diverse hydrogels concerning heavy metal ions, specifically copper, cobalt, and nickel. The impact of key experimental factors, including initial metal concentration, temperature, time, and pH, was inspected via batch adsorption experiments utilizing atomic absorption spectroscopy. It was found that the adsorption of Cu+2‏, Co+2‏ and Ni+2‏ ions is pH-dependent, and the optimal pH for adsorption of Cu+2 is pH 4‏, Co+2 ‏is 5, and Ni+2‏ is 4. The highest metals removal was copper, nickel, and cobalt ions by nano (Fe3O4/gelt/AAm/EDTA) hydrogel with removal percent 98.5% for Cu+2, 96.8%for Ni+2, and 93.9%for Co+2. Graphical Abstract

Fe3O4 nanoparticles decorated on N-doped graphene oxide nanosheets for elimination of heavy metals from industrial wastewater and desulfurization

Finding an effective and excellent pertinent single catalyst material for multipurpose application for the purification of hydrocarbons in fuels (desulfurization), and for efficient removal of heavy metals from industrial effluent is greatly endowed. In the present work, a hybrid nanocomposite of ultrafine magnetite (Fe3O4) nanoparticle embedded on the surface of in-situ nitrogen doped layered GO (NGO) sheets were fabricated by sol-gel method and treatment with microwave irradiation technique is reported for the first time. The results show a high removal efficiency of 97 % for multiple heavy metals (Pb2+, Cd2+, Cu2+, Cr+2, Mn+2etc.) in industrial effluent and as well as in synthetic water with a very good retention performance of 99 %. The composites were tested against the elimination of sulfur from thiophene is 1.495 mmol g−1 is reported high is due to coupling and coordination of nitrogen with FeO and C. Recycling studies showed that the developed composites had excellent recyclability, with <82 % removal at the 5th cycle; its feasibility was evaluated using industrial effluent water and in synthetic water. Surface phenomena studies presented here revealed that the adsorptive removal processes of heavy metals involved π electron donor-acceptor interactions, ion exchange, and electrostatic interactions, along with surface complexation that showed an excellent synergism. A high stability, and retention performance is better than the pure Fe3O4 and NGO sheets. We hope that this study will motivate and give further scope for scientists working on magnetite-based graphene nanocomposites.

Metal adsorption equilibrium response of iron oxide nanoparticles embedded on Acacia (Vachellia nilotica) wood waste under different parametric conditions

The present study reveals cost-effective, environmentally approachable, and efficient adsorbent for the elimination of heavy metals by utilizing the biological synthesis route of nanoparticles (NPs). IONPs (hematite) synthesized from Vachellia nilotica wood waste. Raw wood waste and IONPs were characterized by SEM and FTIR. A batch adsorption process was conducted to study the adsorption of lead (Pb+2) and (Cu+2) ions by raw wood waste and IONPs synthesized from wood waste. Parameters like pH change, temperature, dosage of sorbent, and contact time were performed to provide information about optimal conditions for adsorption. It was found that an adsorbent dosage of 4 g, pH = 7, temperature = 120 °C, and time of 20 min provided high removal efficiency of both metals. With Langmuir and Freundlich adsorption isotherm, experimental data matched well with a high adsorption capacity of 7.5 mg/L for Cu (II) and 0.83 mg/L for Pb (II). Kinetics study shows that equilibrium data supports with pseudo-second-order model with the highest R 2=0.99. Thermodynamics study (ΔGo, ΔHo, and ΔSo) shows that the process is feasible and has an endothermic nature. IONPs provide high removal efficiency with R 2=0.99 with both metals. IONPs proved as efficient adsorbents with high removal efficacy of studied metal as paralleled to raw wood waste.

Recycling of Sewage Sludge: Synthesis and Application of Sludge-Based Activated Carbon in the Efficient Removal of Cadmium (II) and Lead (II) from Wastewater.

The limited supply of drinking water has aroused people's curiosity in recent decades. Adsorption is a popular method for removing hazardous substances from wastewater, especially heavy metals, as it is cheap, highly efficient, and easy to use. In this work, a new sludge-based activated carbon adsorbent (thickened samples SBAC1 and un-thickened samples SBAC2) was developed to remove hazardous metals such as cadmium (Cd+2) and lead (Pb+2) from an aqueous solution. The chemical structure and surface morphology of the produced SBAC1 and SBAC2 were investigated using a range of analytical tools such as CHNS, BET, FT-IR, XRD, XRF, SEM, TEM, N2 adsorption/desorption isothermal, and zeta potential. BET surface areas were examined and SBAC2 was found to have a larger BET surface area (498.386 m2/g) than SBAC1 (336.339 m2/g). While the average pore size was 10-100 nm for SBAC1 and 45-50 nm for SBAC2. SBAC1 and SBAC2 eliminated approximately 99.99% of Cd+2 and Pb+2 out the water under all conditions tested. The results of the adsorption of Cd+2 and Pb+2 were in good agreement with the pseudo-second-order equation (R2 = 1.00). Under the experimental conditions, the Cd+2 and Pb+2 adsorption equilibrium data were effectively linked to the Langmuir and Freundlich equations for SBAC1 and SBAC2, respectively. The regeneration showed a high recyclability for the fabricated SBAC1 and SBAC2 during five consecutive reuse cycles. As a result, the produced SBAC1 and SBAC2 are attractive adsorbents for the elimination of heavy metals from various environmental and industrial wastewater samples.

Assisted Phytoremediation between Biochar and Crotalaria pumila to Phytostabilize Heavy Metals in Mine Tailings.

The increasing demand for mineral resources has generated mine tailings with heavy metals (HM) that negatively impact human and ecosystem health. Therefore, it is necessary to implement strategies that promote the immobilization or elimination of HM, like phytoremediation. However, the toxic effect of metals may affect plant establishment, growth, and fitness, reducing phytoremediation efficiency. Therefore, adding organic amendments to mine tailings, such as biochar, can favor the establishment of plants, reducing the bioavailability of HM and its subsequent incorporation into the food chain. Here, we evaluated HM bioaccumulation, biomass, morphological characters, chlorophyll content, and genotoxic damage in the herbaceous Crotalaria pumila to assess its potential for phytostabilization of HM in mine tailings. The study was carried out for 100 days on plants developed under greenhouse conditions under two treatments (tailing substrate and 75% tailing/25% coconut fiber biochar substrate); every 25 days, 12 plants were selected per treatment. C. pumila registered the following bioaccumulation patterns: Pb > Zn > Cu > Cd in root and in leaf tissues. Furthermore, the results showed that individuals that grew on mine tailing substrate bioaccumulated many times more metals (Zn: 2.1, Cu: 1.8, Cd: 5.0, Pb: 3.0) and showed higher genetic damage levels (1.5 times higher) compared to individuals grown on mine tailing substrate with biochar. In contrast, individuals grown on mine tailing substrate with biochar documented higher chlorophyll a and b content (1.1 times more, for both), as well as higher biomass (1.5 times more). Therefore, adding coconut fiber biochar to mine tailing has a positive effect on the establishment and development of C. pumila individuals with the potential to phytoextract and phytostabilize HM from polluted soils. Our results suggest that the binomial hyperaccumulator plant in combination with this particular biochar is an excellent system to phytostabilize soils contaminated with HM.

Eco-friendly thiol-functionalized magnetic oxygenous carbon nitride nanocomposites for effective elimination of heavy metals

The increased pollution of water resources by toxic heavy metals poses a huge threat to the aqueous ecosystem. Since the low concentrations of heavy metals are often highly toxic but difficult to remove, novel efficient adsorbents still need to be explored. Herein, the superparamagnetic thiol-functionalized oxygenous carbon nitride nanocomposite (CNO/Fe3O4-SH) with multifunctional groups such as –NH2, –OH, –SH, and –COOH was fabricated by a simple and eco-friendly method. The maximum adsorption capacities of Pb2+, As3+, and Cd2+ ions on CNO/Fe3O4-SH at pH = 6 were 80.79, 71.78 and 66.19 mg/g, respectively, when their equilibrium concentrations were 20 mg/L. Under the equilibrium concentration below 0.01 mg/L, the adsorption capacities of these heavy metals over CNO/Fe3O4-SH were much higher than those of other adsorbents. The competitive adsorption investigations showed that the adsorption order in polymetallic solutions was Pb2+ > As3+ > Cd2+. Adsorption kinetics and isotherms studies indicated that the adsorption of Pb2+, As3+ and Cd2+ by CNO/Fe3O4-SH was attributed to monolayer adsorption and the adsorption process was controlled by chemical adsorption. The thermodynamic experiments showed that the adsorption processes were spontaneous and endothermic. After six adsorption/desorption cycles, CNO/Fe3O4-SH maintained its original morphology and adsorption ability, indicating its excellent regeneration performance, which had significant potential application in the decontamination of trace heavy metal ions in water.

Polyvinyl Alcohol‐Conjugated L‐Cysteine: A Novel Metal Pincer for Efficient Heavy Metal Ions Removal from Wastewater

AbstractA facilely prepared composite based on Polyvinyl alcohol anchored‐ L‐cysteine (PVA‐L‐CYS) demonstrated efficient functionality in the elimination of heavy metals (Hg, Cr, Pb, and Cd) from working wastewater. The synthesis of the composite was validated through a comprehensive characterization utilizing various analytical techniques to ensure the composite‘s structural, chemical, and physical properties. At ambient temperature, pH of 4–5.5, interaction time of 15–20 minutes, and concentration of 200 mg/L metal ions, the composite exhibited a maximum retention capacity of 48.5, 25, 45.25, and 44.25 mg/g for Hg, Cr, Pb, and Cd, respectively. Langmuir modeling was establish to be more fitting to the practical results than Freundlich, providing theoretical values of 49.02, 25.97, 46.08, and 44.84 mg/g for Hg, Cr, Pb, and Cd, respectively. The kinetics of PVA‐L‐CYS composite was accurately predicted by model of the pseudo‐first‐order kinetic. Thermodynamic prospects indicated a spontaneous, exothermic, and favorable uptake process at low temperatures. Efficient elution of the heavy metal ions from the overloaded composite was performed using 1 M HNO3. In accordance with WHO and FAO guidelines, the successful elimination of working metal ions from wastewater utilizing the PVA‐L‐CYS composite was demonstrated in a single cycle before discharge into the marine environment.

Sustainable Starch Strategies: Nano and Macro Adsorbents for the Detoxification of Synthetic Dyes and Heavy Metals

The research being conducted explores environmentally friendly techniques for heavy metal and synthetic dye detoxification from aquariums via nano- and macro adsorbents based on starch. In exposure to the urgent demands for sustainable wastewater treatment solutions, the research effort focuses on the development and evaluation of materials made from starch that have enhanced adsorption abilities. The effectiveness of developing and evaluating macro- and nano-sized starch composites and starch-based adsorbents in facilitating the elimination of heavy metals and synthetic colours is determined. The review includes a thorough examination of equilibrium traits kinetics, and adsorption processes, also takes into account how these sustainable starch-based products could be employed in real-world environmental remediation scenarios. The aforementioned findings offer significant additional knowledge regarding how to develop and implement starch-based adsorbents for the long-term and effective detoxification of heavy metals and synthetic colours compared to water.

Solid-State Fluorescent Organic Polymers for Visual Detection and Elimination of Heavy Metals in Water.

Selective sensing and removal of toxic heavy metals from water are highly essential since their presence poses significant health and environmental hazards. Herein, we designed and synthesized a novel fluorescent nonconjugated organic polymer by strategically incorporating two key functional groups, namely, a dansyl fluorophore and dithiocarbamate (DTC). Different characterization techniques, including 1H nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR), and fluorescence spectroscopy, were performed to understand its structure and material properties. The quantum yield of 4.72% and its solid-state fluorescence indicate that it has potential for various applications in several technological and scientific domains. In this study, we investigated a specific application involving the detection and elimination of heavy metals from water. Interestingly, the presence of dansyl and DTC moieties demonstrated remarkable selectivity toward Cu2+, Co2+, Ni2+, Fe3+, and Fe2+ sensing, displaying distinct color changes specific to each metal. Cu2+ resulted in a yellow color, Co2+ showed a green color, Ni2+ displayed a pale yellowish-green color, and Fe2+/Fe3+ exhibited a brown color. The LOD (limit of detection) for each metal was obtained in the nanomolar range by using a fluorescence spectrometer and the micromolar range from UV-visible spectra: 13.27 nM and 0.518 μM for Cu2+, 8.27 nM and 0.581 μM for Co2+, 14.36 nM and 0.140 μM for Ni2+, 14.95 nM and 0.174 μM for Fe2+, and 15.54 nM and 0.33 μM for Fe3+. Moreover, the DTC functionality on its backbone facilitates effective interaction with the aforementioned heavy metals, subsequently removing them from water (except Fe2+ and Fe3+), validating its dual functionality as both an indicator and a purifier for heavy metals in water. The polymer exhibited a maximum adsorption capacity of 192.30 mg/g for Cu2+, 159.74 mg/g for Co2+, and 181.81 mg/g for Ni2+. Furthermore, this approach exhibits versatility in crafting fluorescent polymers with adjustable attributes that are suitable for a wide range of applications.

Bioabsorption of Maize Cob and its Derivative in the Elimination of Heavy Metals from Waste Water in Some Local Government Areas of Kaduna State, Nigeria

Bioabsorption of Maize Cob and its Derivative in the Elimination of Heavy Metals from Waste Water in Some Local Government Areas of Kaduna State, Nigeria

Design and characterization of phosphonic acid-functionalized grafted sepiolite nanohybrids and their adsorption studies for removal of copper ions from aqueous solution.

In this study, we synthesized novel, economically efficient phosphonic acid-functionalized grafted sepiolite nanohybrids for selective elimination of copper ions from water. These nanohybrids were prepared by graft polymerization of glycidyl methacrylate onto sepiolite. We utilized free radical graft polymerization to graft glycidyl methacrylate (GMA) onto silanized sepiolite. The nanohybrids obtained exhibited a grafting percentage of 479% at 0.3 g of KPS initiator, 15% GMA monomer, and after 4 h of reaction. In pursuit of selectively removing metal ions from water, the nanohybrid with the highest grafting (PGE3) was chemically treated with phosphoric acid to introduce phosphonic acid groups on it. FTIR, XRD, SEM, CHO analysis, BET, and TGA analysis were utilized to characterize the developed nanohybrids. Batch adsorption studies were carried out using AAS process, examining the impact of pH, adsorbent weight, contact time, adsorbate concentration, and temperature on the adsorption process. Due to the selectivity of phosphonic acid groups towards copper ions, phosphonic acid-functionalized grafted sepiolite nanohybrid (PGE3-P) was used for copper ions removal from its aqueous solution. The maximum adsorption capacity of PGE3-P adsorbents was 134.5 mg/g for copper ions. The data from kinetic studies suggests that the adsorption process of copper ions followed a pseudosecond-order model. Furthermore, Langmuir isotherm proved to be a more fitting model in equilibrium isothermal investigations. The thermodynamic analysis of the data indicates that the adsorption of copper ions by PGE3-P is an endothermic and spontaneous process. The development of this phosphonic acid-functionalized grafted sepiolite nanohybrid adsorbent is a new contribution into the field of adsorption. The developed material can be utilized as selective adsorbent for elimination of other heavy metals from water.

Performance evaluation of species varied fixed bed biofilm reactor for wastewater treatment of Dhobi Khola outfall, Setopul, Kathmandu, Nepal

The sustainability of wastewater treatment plants poses significant challenges for developing countries, necessitating substantial investment for operation and maintenance. Biofilm reactors seeded with specific species of microorganisms were investigated under controlled environmental conditions. However, the performance evaluation of such reactors under natural conditions remains largely underexplored. This study investigated wastewater treatment capabilities of bench-scale fixed bed biofilm reactors, employing various species (Wastewater Microbes, Pseudomonas, Algae, and a co-culture of Algae and Pseudomonas). The reactors (Treatments and Control) were filled with 28 mm nominal-size local aggregates as packing media, operated under different contact times, and subjected to varying concentrations of heavy metals (Zn, Cd). To assess the reactor performances, the Bland-Altman Plot and Chemical Oxygen Demand (COD) removal kinetics were evaluated.The results revealed that the reactor initiated with a co-culture exhibited the optimal COD removal efficiency, reaching 84 ± 1 %. The reactor initially seeded with wastewater microbes exhibited the highest heavy metal elimination, achieving 94 ± 1 % and 88 ± 1 % removal for Zn and Cd respectively. The wastewater-seeded reactor demonstrated the zero-order COD removal kinetic coefficient (k) of 46.41 mg/L/h at an average influent COD concentration of 558 mg/L at 10 h contact time. While Pseudomonas-seeded reactor demonstrated k = 0.73 mg/L/h at 20 h contact time with 69 mg/L influent COD and heavy metal concentrations Zn = 26 mg/L and Cd = 3.57 mg/L.The findings of this study suggest that variations in environmental conditions, contact time, and heavy metal concentration have minimal impact on the pollutant removal efficacy of the reactors, and provide robust evidence for their viability as a sustainable alternative in municipal wastewater treatment. The study also identifies the possibility of treating specific wastewater characteristics by altering the dominant species in the reactors, paving the way for further research on the efficacy of other microbial genomes in fixed bed biofilm reactors.

Thermal degradation of polyvinyl chloride in the presence of lead oxide: A kinetic and mechanistic investigation

The elimination of toxic heavy metals from metallurgical wastes before its recycling to steel furnaces is essential. Lead oxide (PbO) is a major toxic heavy metal present in electric arc furnace dust (EAFD). The co-recycling of EAFD with Polyvinyl chloride (PVC) followed by water leaching allows the elimination of this material. Herein, an experimental and theoretical kinetic investigation was conducted on the thermal degradation of PVC in the presence of PbO. An inhibiting effect of PbO on the thermal degradation of PVC was observed; the onset PVC de-hydrochlorination temperature increased from 273 to 293 °C. PbO addition also increased the activation energy of PVC mass loss from 148 kJ/mol (PVC) to 173 kJ/mol (PbO-PVC) in the conversion window 5–45 %. The theoretical Density Function Theory (DFT) suggested that the intramolecular hydrogen transfer (IHT) to form H2O on PbO surface exhibited the highest energy barrier at 251.01 kJ/mol, which aligns with the experimental data. The kinetic parameters generated here can be utilised to calculate the appropriate holding temperature and time for the effective removal of PbO from waste EAFD using PVC as a chlorinating additive. This should contribute towards optimising process economics and efficiency.

Rationally engineered core-shell structured Fe0@FeS towards the efficacious synergistic Cr(VI) and Ni(II) removal

As one category of promising and efficacious purification material toward environmentally harmful heavy metals, sulfidated amorphous zero-valent Iron (S@AZVI) exhibits unparalleled removal performance. Due to the disruptive crystal growth however, the irreversible loss of Fe0 component during conventional synthesis route poses a substantial hindrance to its industrial application. To address this, we propose a post-sulfidation strategy to hinder the transformation of Fe0 by altering the shell composition of AZVI from Fe2O3 to FeS, which maintains a remarkable Fe0 content up to 75.7 % over finally obtained S@AZVI, far higher than the material obtained through the one-step sulfidation. Attributing to the synergy of FeS shell and substantial Fe0, S@AZVI demonstrates impressive performance as the lowest free corrosion potential (−1.050 V) and work function (4.058 eV), and subsequently exhibits a notable enhancement in the removal efficiency of Cr(VI) and Ni(II), surpassing AZVI by 1.8 and 2.0 times, respectively. Results reveal that the adsorption, reduction, and coprecipitation constitute the mechanisms governing the removal of Cr(VI) and Ni(II). In practical electroplating wastewater experiments, S@AZVI effectively removes Cr(VI) and Ni(II) within a 60-min timeframe, meeting established emission standards. These findings provide valuable insights for future AZVI material synthesis for heavy metal elimination.

Synergistic effect on simultaneous treatment of Cr(VI) and chloramphenicol using a non-thermal plasma technology

Toxic organic and heavy metal contaminants commonly exist in industrial waste stream(s) and treatment is of great challenge. In this study, a dielectric barrier discharge (DBD) non-thermal plasma technology was employed for the simultaneous treatment of two important contaminants, chloramphenicol (CAP) and Cr(VI) in an aqueous solution through redox transformations. More than 70% of CAP and 20% of TOC were degraded in 60 min, while Cr(VI) was completely removed in 10 min. The hydroxyl radicals were the main active species for the degradation. Meanwhile, the consumption of hydroxyl radicals was beneficial to the reduction of Cr(VI). The synergistic effect was investigated between CAP degradation and Cr(VI) reduction. The reduction of Cr(VI) would be enhanced in the presence of CAP with a low concentration and could be inhibited under a high concentration, because part of hydroxyl radicals could be consumed by the low-concentration CAP and the obtained intermediates with a higher kinetic rate. However, CAP with a high concentration could react with such reductive species as eaq− and •H, which could compete with Cr(VI) and inhibit the reduction. In addition, the presence of Cr(VI) enhanced the degradation and mineralization of CAP; the study of obtained intermediates indicated that the presence of Cr(VI) changed the degradation path of CAP as Cr(VI) would react with reductive species, enhance the generation of hydroxyl radicals, and cause more hydroxylation reactions. Moreover, the mechanism for the simultaneous redox transformations of CAP and Cr(VI) was illustrated. This study indicates that the DBD non-thermal plasma technology can be one of better solutions for simultaneous elimination of heavy metal and organic contaminants in aquatic environments.

Biochar – a sustainable soil conditioner for improving soil health, crop production and environment under changing climate: a review

Land degradation and climate change, two intricately intertwined phenomena, demand appropriate management solutions to effectively tackle the escalating issues of food and nutritional security. In this context, the realm of agriculture confronts formidable challenges in its pursuit of soil resource reclamation, improving water quality, mitigating climate change, and maintaining soil and natural resources for posterity. Central to these aspirations is the preservation of an optimum organic matter, serving as a linchpin threshold is crucial for protecting the physical, chemical, and biological integrity of the soil, while simultaneously sustaining agricultural productivity. To address these multifaceted challenges, the introduction of diverse organic amendments has emerged as a crucial strategy. Noteworthy among these is the application of biochar, which functions as a soil conditioner capable of bolstering soil health, mitigating the impact of climate change, and securing global food security. Biochar is a carbon-enriched substance produced through pyrolysis of assorted biomass waste. It has a larger surface area, higher cation exchange capacity, and an extended carbon storage capability. The strategic integration of biochar production and subsequent soil application engenders an array of benefits, encompassing the amelioration of soil physical properties, augmented retention and the availability of nutrients, and the enhancement of biological activity, resulting in higher agricultural yields and societal benefits through the curtailment of soil to atmosphere greenhouse gas emissions. Additionally, biochar demonstrates its efficacy in the realm of environmental restoration by serving as a medium for extraction and elimination of heavy metals, which often pervade aquatic ecosystems and soil matrices. This review addressed the need for biochar production, characterization, soil health, the possibility for environmental restoration, and crop yield fluctuations owing to climate change.

Investigation of the performance of the combined moving bed bioreactor-membrane bioreactor (MBBR-MBR) for textile wastewater treatment

The present study focused on the investigation of the performance of a Moving Bed Bioreactor coupled with a Membrane Bioreactor (MBBR-MBR) on a small scale for textile wastewater treatment. The parameters examined in this study included the removal efficiency of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (TSS), turbidity, color, and heavy metals (HM). The two reactors were operated consecutively and maintained aerobic conditions. The idea is to reduce the pollutant load significantly through the activity of microorganism attached to the biofilm covered carriers in MBBR and successive membrane filtration. The system demonstrated a favorable outcome even in a smaller hydraulic retention time (HRT) of 1 day, which presents a significant advantage in terms of cost and space saving. The removal effectiveness of COD attained a maximum of 92 %, BOD reached a maximum of 95 %, and the color removal performance obtained a removal efficiency of 87 %. Furthermore, the treatment showed remarkable efficiency in removing up to 100 % of TSS and 96 % of turbidity. Additionally, an evaluation was conducted on the elimination of heavy metals, including Zinc (Zn), Lead (Pb), Chromium (Cr), and Iron (Fe). The efficacy of removing these HMs was found to exceed 85 %. All these favorable outcomes contribute to the improvement of effluent quality, mitigation of contamination hazards, and fouling reduction.

Ru@Co3O4@g-C3N4 as a novel adsorbent for enhanced copper and cadmium abolition

Elimination of heavy metals from contaminated water systems is of prime distress due to their capacity to prompt toxic impact on the flora and fauna. The usage of innovative nano-engineered materials predominantly opens up smart prospects for the treatment of persistent heavy metal adulterated water resources. This study presents an ultrasonic-assisted sol-gel production of Ru@Co3O4@g-C3N4 nanostructure that was utilized to remove Cu+2 and Cd+2 ions from aqueous solutions. The X-ray diffraction investigation revealed the development of RuO2, Co2O3 and g-C3N4 phases, and the relevant elemental composition was verified by the photoelectron spectroscopy and EDX. The dispersion of the metal oxides within the nitride sheets was evidenced by scanning and transmission electron microscopy. The initial metal ions concentration, pH, and contact time effects were investigated through batch experiments. The adsorption isotherm models matched the Langmuir isotherm well, whereas the kinetics model data perfectly fitted the pseudo-second-order model. The maximum adsorption capacities of Cu+2 and Cd+2 ions on the nanocomposite Ru@Co3O4@g-C3N4 were 696.9 and 564.5 mg/g, respectively. A mechanism based on a viable covalent type of bonding developed by the delocalized -conjugated electrons of the triazine ring and functional groups were efficiently involved in the metal ions anchoring and ultimate elimination. Thus, the suitability of the Ru@Co3O4@g-C3N4 nanocomposite for eradicating heavy metals, including Cu+2 and Cd+2, was established.

Remediation of mine overburden and contaminated water with activated biochar derived from low-value biowaste

BackgroundMines can be regarded as the economic backbone of India with a contribution of 10–12 % towards the gross domestic production with industrial demand. It gives rise to environmental problems like soil, water and air pollution. The active mines generate lots of waste rock and wastewater that contaminate nearby soil and water bodies with heavy metals. MethodsThe elimination of heavy metals by suitable amendments is emerging as a potential solution to such problems. Biochar, a carbon rich, stable, alkaline and porous product of thermo-chemical conversion of biomass has emerged as a promising adsorbent of heavy metals. Conversion of these biowastes into biochar is a sustainable approach as it fulfills multiple objectives of waste utilization, and pollution abatement. Significant findingsDue to its large surface area, biochar can restrain heavy metals while modified biochar has an increased potential for adsorption with an increased surface area. The review emphasizes the type of mines, overburden generation, their impact on soil and water, and the utility of different biowastes available to be mobilized into biochar for remediation of contaminated water and soil. It also bridges the gap in the current knowledge on the activation techniques of biochar with heavy metals remediation.

Floating Aquatic Macrophytes in Wastewater Treatment: Toward a Circular Economy

Floating aquatic macrophytes have a high level of proficiency in the removal of various contaminants, particularly nutrients, from wastewater. Due to their rapid growth rates, it is imperative to ensure the safe removal of the final biomass from the system. The ultimate macrophyte biomass is composed of lignocellulose and has enhanced nutritional and energy properties. Consequently, it can serve as a viable source material for applications such as the production of bioenergy, fertilizer and animal feed. However, its use remains limited, and in-depth studies are scarce. Here, we provide a comprehensive analysis of floating aquatic macrophytes and their efficacy in the elimination of heavy metals, nutrients and organic pollutants from various types of wastewater. This study offers a wide-ranging scrutiny of the potential use of plant biomasses as feedstock for bioenergy generation, focusing on both biochemical and thermochemical conversion processes. In addition, we provide information regarding the conversion of biomass into animal feed, focusing on ruminants, fish and poultry, the manufacture of fertilizers and the use of treated water. Overall, we offer a clear idea of the technoeconomic benefits of using macrophytes for the treatment of wastewater and the challenges that need to be rectified to make this cradle-to-cradle concept more efficient.