Metal Reduction Research Articles

Enrichment and catalysis effect of 2D/2D g-C3N4/Ti3C2 for promoting organic matter degradation and heavy metal reduction in plasma systems: Unveiling the promotion and redox mechanism.

This work proposes a novel plasma-assisted 2D/2D g-C3N4/Ti3C2 system for treatment of organics-heavy metals composite wastewater. Unlike traditional materials in plasma system, 2D/2D g-C3N4/Ti3C2 not only improved the mass transfer efficiency of plasma by gathering both reactive species and pollutants onto the surface, but also induced photocatalytic reactions. Besides, the higher specific surface area and faster carrier separation rate can enhance the oxidation and reduction activity, and then promoted organic matter degradation and heavy metal reduction. Remarkably, the removal efficiency of sulfamethoxazole (SMX) and Cr(VI) increased by 16.5% and 73.1% respectively when introducing 2D/2D g-C3N4/Ti3C2. Roles of·OH,·H,·O2-, 1O2, e-, and h+ in SMX oxidation and Cr(VI) reduction are clarified. The primary aggregated·OH and 1O2 dominate the degradation of SMX. The influencing factors, synergistic mechanism between plasma and catalyst, and redox mechanism were clarified. This work provides a breakthrough idea for treatment of organics-heavy metals composite wastewater.

A Decade-Long Comparison of Heavy Metal(loid)s in the River and Children’s Health Risk Assessment of an E-Waste Recycling Area

Informal e-waste recycling can cause serious heavy metal(loid) pollution to nearby bodies of water, thereby increasing the risk of heavy metal exposure to local residents. This study investigates metal(loid) pollution levels in the Lianjiang River, which flows through Guiyu, an e-waste recycling town in Shantou, Guangdong. In 2009 and 2020, water samples from the Lianjiang River were taken, and the levels of 12 metal(loid)s (V, Cr, Mn, Sr, Ni, Cu, Zn, As, Se, Cd, Ba, and Pb) were measured by ICP-MS. In total, 380 valid questionnaires from Guiyu kindergarten children were selected to assess child health. Exposure health risks for children were calculated using two forms of exposure (dermal and inhalation) and statistical methods (multiple linear regression and Bayesian kernel machine regression—BKMR). The concentrations of Mn, Ni, Pb, and Cd in 2009 were significantly higher than those in 2020. The concentration of heavy metal(loid)s had been decreasing in 2020. The non-carcinogenic risk levels of the 12 metal(loid)s in both exposure routes were at an acceptable risk level. The average carcinogenic risk levels for As, Cr, Ni, Pb, and Cd exceeded the ILCRi <10–6 acceptable range. According to MLR, it was found that daily oral intake doses of Pb [β(95% CI): −0.949 (−1.596, −0.863), p < 0.001 and Se [β(95% CI): −0.911 (−1.888, −0.092), p = 0.031] were negatively associated with body mass index. A BKMR model was developed, through which the synergistic effects of co-exposure to 12 heavy metal(loid)s on growth and development indicators in children were analyzed. Concentrations of heavy metal(loid)s in rivers near e-waste recycling sites have been decreasing for 10 years. It was found that the growth and development of children are affected by the intake of heavy metal(loid)s in water. The reduction in heavy metal(loid) contamination in e-waste recycling areas needs to be continued, and concern about its impact on children’s health must remain.

Isomerism in Phenyl 2‐Pyridyl Ketoxime Metal Complexes

AbstractThe octahedral complex [RhCl2(ppkoH)(ppko)] (1) was obtained from the reaction between RhCl3 and phenyl 2‐pyridyl ketoxime (ppkoH). Attempts to prepare the corresponding octahedral platinum compound from K2PtCl6 gave instead the square planar [Pt2+(ppko)2] (2), but when the halogen was changed to bromine, the octahedral [Pt4+Br2(ppko)2] (3) was formed. The crystal structures were determined by X‐Ray crystallography. All the compounds have two N,N‐chelating oxime ligands. In 1, one of them is deprotonated, while in 2 and 3 both ligands are deprotonated. Compounds 1 and 3 have two halogen ligands in trans position. In 1 the oxime groups are situated mutually in cis position with an intramolecular hydrogen bond between the two N−O(H) groups. The formation of 2 involves reduction of the platinum metal and the complex has oximes in trans position to each other. Compound 3 has an all‐trans geometry. Since octahedral and square planar compounds have a possibility to isomerism, we studied the relative stability of different geometries by DFT calculations. A mixture of isomers is likely to be formed in the reactions, but the most stable form was found to crystallize. The properties of the electron density in the preferred isomers were also investigated via QTAIM methods.

Cu-Doped V-Based MOF Derivative VO2@Cu-VMOF as a Cathodic Catalyst for Electro-Fenton Degradation of Antibiotics.

In this study, the VO2@5%Cu-VMOF/graphite felt (GF) is prepared as an electro-Fenton cathode via hydrothermal process and low-temperature carbonization for efficient antibiotics degradation. The VO2@5%Cu-VMOF/GF cathode exhibit great ciprofloxacin (CIP) degradation performance over the pH range of 2.1-7.2, and CIP removal reached 98.1% within 60min at a pH of 3.4, with corresponding total organic carbon (TOC) removal of 68.7%. The cathode also showed desired catalytic performance toward various antibiotics decomposition. The great catalytic activity of the VO2@5%Cu-VMOF/GF cathode is attributed to lattice strain induced by Cu doping, and the elimination of the overpotential difference between the optimal oxygen reduction potential (OP ORR) and optimal metal reduction potential (OP MRR). Density Function Theory (DFT) calculations showed that Cu doping facilitated electrons accumulation around V atoms, and thus increased the content of low-valence metals in the cathode material. Four possible degradation pathways for CIP are proposed and intermediate toxicity is evaluated. This work advances the design and application of MOF derivatives as electro-Fenton cathodic materials for emerging contaminants degradation.

Fermi energy level synergistic Bi-based electron bridge construction of Z-type heterojunctions to accelerated photogenerated charge transfer for photostability and contaminant mineralization

Advanced oxidation technologies offer new opportunities for pollutant degradation. Despite the existence of numerous photocatalyst heterojunctions for advanced oxidation, their charge transfer and separation efficiency is low due to inadequate interfacial modulation, especially for Type II heterojunctions. Here, through metal reduction, metal defects with regulating the Fermi level and metal electron bridges with facilitate the separation of photo-generated carriers, facilitating the transition from Type II to Z-type heterojunctions. Herein, we designed a Z-Scheme photocatalyst with Bi-based electron bridges (referred to as ‘fishbone-like’ BiVO4/Bi/CuO) synthesized through in situ reduction, utilized for RhB degradation. Under visible light irradiation, the degradation rate of RhB up to 99 % within 120 min, outperforming most previously reported photocatalysts. Notably, the well-designed BiVO4/Bi/CuO exhibits as reaction rate of 4.13 × 10-2 ·min−1, which is 18 times higher than the pure BiVO4. The BiVO4/Bi/CuO photocatalyst demonstrates exceptional stability over 6 reaction cycles spanning 15 h, due to strengthened contact interface of BiVO4/Bi/CuO. The metal Bi can induce the surface plasmon resonance (SPR) effect, enhancing light absorption. Furthermore, Bi-based electron bridges significantly promote the charge transfer across the Z-type heterojunction interface, which were verified by assorted experimental outcomes and density functional theory (DFT) calculations. This work represents a promising platform for the development of highly efficient and stable photocatalysts that have potential in Pollutant degradation applications.

Enhancing Domestic Wastewater Treatment: Integrating Vermifiltration and Biochar for Heavy metal and Microplastic Reduction and By-Product Utilization

Enhancing Domestic Wastewater Treatment: Integrating Vermifiltration and Biochar for Heavy metal and Microplastic Reduction and By-Product Utilization

Pyrolysis of industrial hemp biomass from contaminated soil phytoremediation: kinetics, modelling transport phenomena and biochar-based metal reduction

Phytoremediation is the use of vegetation for the in situ treatment of contaminated environments. After plants have been used for phytoremediation of soils, their biomass can be used for example as value-added products or converted by thermochemical processes. Large-scale application of pyrolysis technology for phytoremediation biomass requires accurate predictive kinetic models and a characterization of the toxicity of the materials produced. The pyrolysis of industrial hemp (Cannabis sativa L.) was investigated on a laboratory scale by varying the process conditions and accurately modelled by considering four pseudo-components with first reaction order. The average value of the coefficients of determination is 0.9980. Biomass and biochar were characterized and the main components of the gas phase were monitored. We found Cd, Pb, and Zn in the roots, although in lower amounts than in the soil. Especially the leaves and stems showed negligible traces of these elements, so that these parts can be used directly, even if the hemp was grown on the polluted soil. After pyrolysis, the concentration of pollutants in the solid fraction decreased, which could be attributed to the reduction of metal oxides (or salts) to elemental form and subsequent evaporation. This pyrolysis process has the potential to treat heavy metal-rich biomass, with gas phase purification via condensation, yielding agricultural-grade biochar, CO-rich gas and a highly concentrated heavy metal stream in absorbent material.

Dual Photoredox and Titanium Catalyzed Regioselective Allenylation of Aldehydes via Reductive Radical‐Polar Crossover

Comprehensive SummaryThe direct reductive coupling of carbonyl compounds with propargyl halides is a powerful and reliable tool in the synthesis of α‐allenols. However, stoichiometric metal reductants, harsh reaction conditions and a variety of additional additives are required in the traditional strategies. Additionally, the reactivity and regioselectivity control remains an elusive challenge. Herein, we developed the Ti‐catalyzed regioselective reductive coupling of readily available aldehydes and racemic propargyl bromides to rapidly access a wide range of α‐allenols. This method proceed efficiently in a reductive radical‐polar crossover manner featuring mild conditions, excellent regioselectivity control, broad substrate scope, and eco‐friendliness. Preliminary mechanistic studies support the radical‐involved catalytic cycle. And the DFT calculations demonstrate that the regioselectivity is determined by the Zimmerman‐Traxler‐type transition states.

Z-scheme driven charge transfer in g-C3N4/α-Fe2O3 nanocomposites enabling photocatalytic degradation of crystal violet and chromium reduction

In this study, we demonstrated the design and fabrication of iron oxide-embedded protonated graphitic carbon nitride (α-Fe2O3/p-g-C3N4) nanocomposites for photocatalytic dye degradation and heavy metal reduction applications under sunlight irradiation. The developed nanocomposites, with varying weight percentages of α-Fe2O3, were characterized for their structural (XRD, FTIR, XPS), optical (absorption and photoluminescence), morphological (FE-SEM, TEM), and electrochemical (EIS) properties to elucidate their structure-property relationships. The synthesis method ensures the uniform dispersion of α-Fe2O3 nanoparticles, with a particle size range of 50–60 nm, onto p-g-C3N4. XPS analysis suggests the formation of an electrical layer at the interface of α-Fe2O3/p-g-C3N4, facilitating the formation of a Z-scheme heterojunction. The photoluminescence and EIS spectra of the nanocomposite indicated effective separation and transfer of photo-induced charge carriers, aided by a reduced bandgap energy of ∼2.63 eV. Notably, the optimized 10 wt% α-Fe2O3/p-g-C3N4 nanocomposite exhibited superior photocatalytic activity, degrading nearly 100 % of crystal violate dye and reducing 98 % of Cr(VI) ions, compared to bare p-g-C3N4, which degraded around 43 % of the dye and reduced 39 % of Cr(VI) ions under sunlight irradiation. Scavenger studies indicated that α-Fe2O3/p-g-C3N4 nanocomposites produce adequate superoxide anions and hydroxyl radicals for dye degradation and heavy metal ion reduction. The composite also demonstrated consistent recyclability up to 5 cycles with around 100 % cyclical efficiency. The pH-dependent photoreduction and cyclic dye degradation by the 10 wt% α-Fe2O3/p-g-C3N4 photocatalyst indicated excellent stability, making it suitable for the treatment of multi-pollutant wastewater.

Microbial fuel cells: A potent and sustainable solution for heavy metal removal

The global water pollution problem is becoming increasingly crucial. One of the major contributors to water pollution is the presence of heavy metals. Heavy metals pose significant threat to both humans and all ecosystems. Various factors influence the removal of heavy metals from wastewater, including pH, temperature, natural organic matter (NOM), and ionic strength, which vary based on the chemical properties of the pollutants. More effective and modern approaches receive attention and extensively researched to substitute traditional methods such as adsorption, membrane filtration, and chemical-based separation. Among these methods, Microbial fuel cells (MFCs) are particularly intriguing. This review article focuses on MFCs and their potential applications in various fields, including clean water production. MFCs represent an innovative technology that not only generates electricity, but also demonstrates significant potential for heavy metal removal from wastewater. Cathodic chamber of MFCs effectively reduces heavy metals, while organic substrates act as carbon and electron donors in the anodic chamber. Through various mechanisms, including direct and indirect metal reduction, biofilm formation (metal sequestering), electron shuttling, and synergistic interactions among microbial communities, microorganisms exhibit remarkable efficiency in removing metals. Studies showed that dual- and single-chamber MFCs could efficiently remove a range of heavy metals, including chromium, cobalt, copper, vanadium, mercury, gold, selenium, lead, magnesium, manganese, zinc, and sodium, while simultaneously generating electricity, achieving high removal efficiencies ranging from 25% to 99.95%. This range of efficiency varies depending on the specific contaminant being targeted, the concentration of the contaminant, as well as the operating conditions such as pH and temperature. Moreover, MFCs demonstrated a wide range of power outputs, typically ranging from 0.15 W/m² to 6.58 W/m², depending on the specific configuration and conditions. These findings underscore the potential of MFCs as a sustainable and efficient approach for both wastewater treatment and energy generation.

Modular Synthesis of Heterobenzylic Amines via Carbonyl Azinylative Amination.

Transformations enabling the synthesis of α-alkyl, α'-2-azinyl amines by addition of 2-heteroaryl-based nucleophiles to in situ-generated and non-activated alkyl-substituted iminium ions are extremely rare. Approaches involving classical 2-azinyl organometallics, such as the corresponding Grignard reagents, often fail to produce the desired products. Here, we report an operationally straightforward solution to this problem through the development of a multicomponent coupling process wherein a soft 2-azinyl indium nucleophile, generated in situ from the corresponding 2-iodo heteroarene and indium powder, adds to an iminium ion that is also formed directly in the reaction. This modular carbonyl azinylative amination (CAzA) displays a broad scope and only a metal reductant is needed to generate a reactive 2-azinyl nucleophile. Beyond the addition to iminium ions, the 2-azinyl addition to polyfluoromethyl ketones forms the corresponding tertiary alcohols. Together, the products of these reactions possess a high degree of functionality, are typically challenging to synthesize by other methods, and contain motifs recognized as privileged in the context of pharmaceuticals and agrochemicals.

Biaryl Anion Radical Formation by Potassium Metal Reduction of Aryl Isocyanates and Triaryl Isocyanurates.

The potassium metal reduction of aryl isocyanates (aryl = phenyl, p-tolyl, 3,5-dimethylphenyl, 4-biphenylyl, and 1-naphthyl) in THF with 18-crown-6 or in HMPA results in the formation of the corresponding triaryl isocyanurate anion radicals. Continued exposure to potassium results in loss of the isocyanurate anion radical and the eventual formation of the respective biaryl anion radical. The 1,1'-binaphthyl anion radical is found to undergo a cyclodehydrogenation reaction, which leads to formation of the perylene anion radical. When authentic triaryl isocyanurates are reduced with metal, the heterocyclic ring undergoes fragmentation with elimination of carbon monoxide to produce a triarylbiuret dianion. This ring opening reaction is initiated by the two-electron reduction of the neutral isocyanurate species. The biaryl anion radical is formed when the biuret dianion is reduced further with metal. A possible mechanism for biaryl formation involves a heterolytic cleavage of an aryl C-N bond and release of an aryl radical once the triarylbiuret dianion is further reduced. A subsequent intermolecular reaction between two aryl radicals forms the corresponding biaryl, which can then be reduced to the anion radical. Notably, when a mixture of two different triaryl isocyanurate compounds is reduced in solution, the corresponding mixed biaryl anion radical is generated.

Synthetic Challenges toward Modeling Formate Dehydrogenases Using [WVI≡S] Complexes Supported by a Tetradentate [N2S2]4- Ligand.

This report documents our attempts at synthesizing a terminal [WVI≡S] complex supported by a tetradentate, diamido/dithiolate ligand ([N2S2]4-). The target compound was selected because it would serve as a synthetic model for the active sites of formate dehydrogenase (FDH) enzymes. Although the desired [N2S2]WVI≡S species was observed as an NEt3 adduct by mass spectrometry in one case, generally unwanted side reactions prevented isolation and definitive characterization of the target compound. Instead, isolated products characterized by X-ray crystallography included {[N2S2]H}WVI(S2)Cl from redox chemistry of the terminal sulfide, ([N2S2]WVI)2(μ-[N2S2]) from dissociation of the terminal sulfide, ({[N2S2]H}WV)2(μ-S)2 from metal reduction and μ-sulfide bridge formation, and {[N2S2]H}2 from disulfide bond formation via thiolate redox chemistry. A product formed from adventitious exposure to air/moisture, {[N2S2]H2}WVI(O)2, was also characterized. The diverse range of products formed simply from attempted metalation of the [N2S2]4- ligand with Cl4WVI≡S highlights the synthetic challenges toward building active sites that are structurally faithful to FDH.

Synthesis of metallic nanoparticles using biometabolites: mechanisms and applications.

Bio-metabolites have played a crucial role in the recent green synthesis of nanoparticles, resulting in more versatile, safer, and effective nanoparticles. Various primary and secondary metabolites, such as proteins, carbohydrates, lipids, nucleic acids, enzymes, vitamins, organic acids, alkaloids, flavonoids, and terpenes, have demonstrated strong metal reduction and stabilization properties that can be utilized to synthesize nanomaterials and influence their characters. While physical and chemical methods were previously used to synthesize these nanomaterials, their drawbacks, including high energy consumption, elevated cost, lower yield, and the use of toxic chemicals, have led to a shift towards eco-friendly, rapid, and efficient alternatives. Biomolecules act as reducing agents through deprotonation, nucleophilic reactions, transesterification reactions, ligand binding, and chelation mechanisms, which help sequester metal ions into stable metal nanoparticles (NPs). Engineered NPs have potential applications in various fields due to their optical, electronic, and magnetic properties, offering improved performance compared to bulkier counterparts. NPs can be used in medicine, food and agriculture, chemical catalysts, energy harvesting, electronics, etc. This review provides an overview of the role of primary and secondary metabolites in creating effective nanostructures and their potential applications.

Nickel/Photoredox-Catalyzed Asymmetric Three-Component Cross-Coupling To Access Enantioenriched 1,1-Diaryl(heteroaryl)alkanes.

An enantioselective 1,2-dicarbofunctionalization of vinyl (hetero)arenes with alkyl bromides and aryl bromides through nickel/photoredox catalysis is described. This three-component enantioselective domino alkyl arylation of vinyl (hetero)arenes could generate a diverse array of enantioenriched 1,1-diaryl(heteroaryl)alkanes with good to excellent yields (up to 88%) and high enantioselectivities (up to 99% ee). This transformation could proceed well under mild conditions with excellent chemo- and regioselectivity due to the avoidance of the use of air- and moisture-sensitive organometallic reagents and stoichiometric metal reductants. Mechanistic studies suggested that the alkyl radical is generated via NiI species or photocatalyst.

Catalytic Asymmetric Barbier Reaction of Ketones with Unactivated Alkyl Electrophiles.

The Barbier reaction is a reductive-type addition of an aldehyde or ketone with an organic electrophile in the presence of a terminal metal reductant, providing a straightforward and efficient method for carbon-carbon bond formation. This reaction possesses the advantage of circumventing the preparation of moisture- and air-sensitive organometallic reagents. However, the catalytic Barbier reaction of ketones to construct tetrasubstituted stereogenic centers is largely underdeveloped, despite its great potential for accessing synthetically challenging chiral tertiary alcohol. Particularly, the leveraging of unactivated alkyl electrophiles as coupling components is still rarely exploited. Herein, we disclose a photoredox-assisted cobalt-catalyzed asymmetric alkylative Barbier-type addition reaction of ketones to address the aforementioned challenges, thereby allowing for the construction of highly congested tetrasubstituted carbon centers. The alkyl addition fragments could be either readily accessible unactivated alkyl halides or redox-active esters generated through a decarboxylative pathway. Both types of alkyl electrophiles include primary, secondary, and tertiary ones, thus affording diverse enantioenriched tertiary alcohols with a broad substrate scope. This enantioselective protocol is applied for the expedient synthesis of core structure of Sofdra, a very recent FDA-approved drug in 2024. The newly developed bisoxazolinephosphine (NPN) ligand enables high enantioselectivity in this asymmetric reductive addition process.

Corrosion of Copper, Cupronickel, Nickel Aluminium Bronze and Super-Duplex Stainless Steel Rotating Cylinder Electrodes in Seawater under Turbulent Flow Conditions

The corrosion of uncoated metals in a marine environment restricts the choice of suitable engineering metals and alloys. Anodic dissolution of metal and cathodic reduction of oxygen are important processes and formation of a surface oxide film can affect both electrode reactions. Charge transfer and mass transfer data can provide information on corrosion rate and mechanism. Several metals and alloys having a history of use in marine engineering are considered, including copper, two copper alloys (cupronickel and nickel aluminium bronze) plus a more recent addition to strong, corrosion resistant alloys (a super duplex stainless steel). The rotating cylinder electrode offers the benefits of a controlled, turbulent flow of electrolyte, facilitating controlled mass transfer in a compact cell geometry which is well-suited to bench-top operation. These features are illustrated using a variety of electrochemical techniques, including open-circuit potential vs time monitoring, linear sweep voltammetry, rotation speed step- or potential step current transients and linear polarisation resistance measurements. Seawater taken from Langstone Harbour, Hampshire, UK, was filtered, air-saturated, pH 8.0 and maintained at 25 °C. Dimensionless group correlations and graphical plots (using an analogous approach to the Koutecky-Levich equation for an RDE) enabled contributions of charge transfer-, mixed- and mass transfer- controlled data to be appreciated, allowing the Tafel slopes of electrode reactions, the diffusion coefficient of dissolved oxygen, the mass transfer coefficient for oxygen reduction and the mean corrosion rate to be estimated.

Composting as a Cleaner Production Strategy for the Soil Resource of Potato Crops in Choconta, Colombia

Choconta is the municipality in Colombia with the greatest prevalence of potato planting, representing 70.90% of the total territory. However, this crop has been affected by the presence of pests, diseases, and chemical contaminants from pesticides and chemical fertilizers that deteriorate the soil and, therefore, the quality of the final product. Compost (organic waste with specific characteristics and made from waste generated in Choconta) was studied as a sustainable production strategy to increase soil quality and thereby the quality of the local potato crop. For this purpose, a 3 × 2 experiment design was implemented with three treatments (0%, 25%, and 50% compost) and two variables (young potato and mature potato) in duplicate for 4 months. In this experiment, the use of compost led to an improved final product, which went from a floury texture to a dense and creamy texture. The use of compost also reduced the levels of heavy metals, such as lead, with a higher removal in treatment 3 (50% composting). The estimated direct cost of the composting process was USD 280.85, slightly lower than that of the application of fertilizers at USD 294.48. The use of fertilizers has a higher environmental impact due to the use of chemical products that have environmental and health implications. Using compost did not influence tuber harvest time but had a positive impact on tuber texture quality and on soil resources through the reduction in heavy metals, especially lead (16.40–18.03 ppm for treatment 1, 17.96–18.49 ppm for treatment 2, and 15.67–17.88 ppm for treatment 3). Using compost could be environmentally and economically beneficial for local farmers, and it promotes the circular economy and sustainable communities.

Enhanced Pollutant Removal and Antifouling in an Aerobic Ceramic Membrane Bioreactor with Bentonite for Pharmaceutical Wastewater Treatment.

This study examined the impact of adding bentonite clay (concentration of 1.5 to 10 g/L) to a pilot-scale aerobic ceramic membrane bioreactor (AeCMBR) for treating pharmaceutical wastewater (PhWW). The hydraulic retention time (HRT) was maintained at 24 h; the dissolved oxygen was between 2 mg/L (on) and 4 mg/L (off) throughout operation. Organic and nitrogen pollution removal rates and heavy metal (Cu, Ni, Pb, Zn) reduction rates were assessed. The chemical oxygen demand (COD) removal efficiency exceeded 82%. Adsorption improved ammonia (NH4+) removal to 78%; the addition of 5 g of bentonite resulted in a 38% improvement compared with the process without bentonite. The average nitrate concentration decreased from 169.69 mg/L to 43.72 mg/L. The average removal efficiencies for Cu, Ni, Pb and Zn were 86%, 68.52%, 46.90% and 56.76%, respectively. Bentonite at 5 g/L significantly reduced membrane fouling. The cost-benefit analysis enabled us to predict that the process will meet the multiple objectives of durability, treatment performance and economic viability. The combination of an AeCMBR and bentonite adsorption has proven to be a valuable solution for treating highly polluted wastewater.

Green integrative large scale treatment of tannery effluent, CO2 sequestration, and biofuel production using oleaginous green microalga Nannochloropsis oculata TSD05: An ecotechnological approach

In this present investigation, the freshwater microalga Nannochloropsis oculata TSD05 was used to demonstrate multiforius environmental applications viz., bioremediation of tannery effluent, carbon sequestration, and green renewable biodiesel production from treated microalgal biomass. The microalga Nannochloropsis oculata TSD05 was exhibited unique heavy metal reduction capabilities and reduced significant amount of heavy metals viz., 96.62% of copper (Cu2+), 99.9% of chromium (Cr3+), 98.36% of zinc (Zn2+), 98.71% of cadmium (Cd2+), 97.96% of lead (Pb2+), 98.88% of Cobalt (Co2+), and 98.76% of nickel (Ni2+). The biosorption capacity rate (qmax) of heavy metals reduction and highest R2 of 97.84% exhibited at 12 days of effluent treatment by Langmuir and Freundlich isotherm models. The phytotoxicity analysis was tested againt treated tannery effluent using Vigna radiate, Sapindus muukorossi seeds and 98.45%, 99.05% seeds were germinated. The Nannochloropsis oculata TSD05 microalga was utilized 98.45% of CO2 by biofixation kinetics, 372 mg g−1 of lipid, 3.65 mg mL−1 of biomass and 4.64 mLg−1 of biodiesel were produced. The produced biodiesel was confirmed and identification of 18 fatty acid methyl ester (biodiesel) compounds using GCMS. The recognition of 17 functional groups was identified using FTIR analysis and the microalga Nannochloropsis oculata TSD05 potential for sustainable and renewable green energy production. The potential future application of Nannochloropsis oculata TSD05 is to increase lipid production and biodiesel yield. Scaling up the bioremediation process can also validate these microalga's feasibility for use in wastewater treament. Enhancing heavy metal biosorption and carbon sequestration efficiency through genetic engineering could also maximize environmental benefits.