Nanoarchitectonics Design Strategy of Metal-Organic Framework and Bio-Metal-Organic Framework Composites for Advanced Wastewater Treatment through Adsorption.

Freshwater depletion is an alarm for finding an eco-friendly solution to treat wastewater for drinking and domestic applications. Though several methods like chlorination, filtration, and coagulation-sedimentation are conventionally employed for water treatment, these methods need to be improved as they are not environmentally friendly, rely on chemicals, and are ineffective for all kinds of pollutants. These problems can be addressed by employing an alternative solution that is effective for efficient water treatment and favors commercial aspects. Metal organic frameworks (MOFs), an emerging porous material, possess high stability, pore size tunability, greater surface area, and active sites. These MOFs can be tailored; thus, they can be customized according to the target pollutant. Hence, MOFs can be employed as adsorbents that effectively target different pollutants. Bio-MOFs are a kind of MOFs that are incorporated with biomolecules, which also possess properties of MOFs and are used as a nontoxic adsorbent. In this review, we elaborate on the interaction between MOFs and target pollutants, the role of linkers in the adsorption of contaminants, tailoring strategy that can be employed on MOFs and Bio-MOFs to target specific pollutants, and we also highlight the effect of environmental matrices on adsorption of pollutants by MOFs.

Metal-organic frameworks (MOFs) for energy production and gaseous fuel and electrochemical energy storage applications.

The increasing energy demands in society and industrial sectors have inspired the search for alternative energy sources that are renewable and sustainable, also driving the development of clean energy storage and delivery systems. Various solid-state materials (e.g., oxides, sulphides, polymer and conductive nanomaterials, activated carbon and their composites) have been developed for energy production (water splitting-H2 production), gaseous fuel (H2 and CH4) storage and electrochemical energy storage (batteries and supercapacitors) applications. Nevertheless, the low surface area, pore volume and conductivity, and poor physical and chemical stability of the reported materials have resulted in higher requirements and challenges in the development of energy production and energy storage technologies. Thus, to overcome these issues, the development of metal-organic frameworks (MOFs) has attracted significant attention. MOFs are a class of porous materials with extremely high porosity and surface area, structural diversity, multifunctionality, and chemical and structural stability, and thus they can be used in a wide range of applications. In the present review, we precisely discuss the interesting properties of MOFs and the various methodologies for their synthesis, and also the future dependence on the valorization of solid waste for the recovery of metals and organic ligands for the synthesis of new classes of MOFs. Subsequently, the utilization of these interesting characteristics for energy production (water splitting), storage of gaseous fuels (H2 and CH4), and electrochemical storage (batteries and supercapacitors) applications are described. However, although MOFs are efficient materials with versatile uses, they still have many challenges, limiting their practical applications. Therefore, finally, we highlight the challenges associated with MOFs and show the way forward in overcoming them for the development of these highly porous materials with large-scale practical utility.

Synchronous COD removal and nitrogen recovery from high concentrated pharmaceutical wastewater by an integrated chemo-biocatalytic reactor systems.

Present report, an investigation of highly concentrated and low bio-degradable pharmaceutical wastewater (HCPWW) treatment; simultaneously ammoniacal nitrogen recovery for struvite fertilizer. The use of multiple solvents and many formulation processes in HCPWW, resulting highly refractory chemicals. Here, in this study focused on evaluation of chemo-biocatalysts for the removal of refractory organics, nitrogen recovery from HCPWW. The initial organics, and nitrogen content in HCPWW was 20,753 ± 4606 mg/L; BOD, 6550 ± 1500 mg/L and NH4+-N, 1057.9 ± 185.8 mg/L. Initially, the biodegradability (BOD5: COD ratio from 0.32 to 0.45) of HCPWW, which was improved by heterogeneous Fenton oxidation (HFO) processes, and porous carbon (PCC, 30 g/L), along with FeSO4.7H2O, 200 mg/L and H2O2 (30% v/v), 0.4 ml/L were used as a catalyst in a weakly acidic medium. For the biocatalytic processes, the microbial culture cultivated from sewage and incorporated into a Fluidized Immobilized Carbon Catalytic Oxidation reactor (FICCO), and dominant species are Pseudomonas Putida sp., Pseudomonas Kilionesis sp., and Pseudomonas Japonica sp., which is identified by using 16 S rDNA sequencing analysis. The COD and BOD5 removal efficiency of 65-93% and 70-82%, and follow the pseudo-second-order kinetic model with the rate constants of 1.0 × 10-4 L COD-1 h-1, 1.5 × 10-3 L COD-1 h-1 and 3.0 × 10-3 L COD-1 h-1 in the HFO-FICCO-CAACO catalytic processes. The optimized hydraulic retention time (HRT) of FICCO reactor was 24 h, and 1 h for the Chemo-Autotrophic Activated Carbon Oxidation (CAACO) reactor for maximum organics removal. MAP (Magnesium Ammonium Phosphate precipitation) process showed 90% of NH4+-N elimination and recovered it as a struvite fertilizer at an optimum molar ratio of 1:1.3:1.3 (NH4+-N: Na2HPO4.2H2O: MgO). FT-IR, UV-visible, and UV-fluorescence data confirm the effective elimination of organics. Hence, this integrated treatment system is appropriate for the management of pharmaceutical wastewater especially elimination of complex organic molecules and the recovery of nitrogen in the wastewater.

Sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene/sulfonated poly(ether sulfone) and hexagonal boron nitride electrolyte membrane for fuel cell applications.

Novel proton exchange membranes consisting of sulfonated polystyrene ethylene butylene polystyrene (sPSEBPS), sulfonated poly ether sulfone (SPES) and hexagonal boron nitride (hBN) were fabricated using a facile solution casting technique. The PSEBPS polymer was functionalized using chlorosulfonic acid as the sulfonating agent. Polymerization was typically conducted by taking three different monomers, namely 3,6-dihydroxy naphthalene-2,7-disulfonic acid disodium salt, 4,4'-dichlorodiphenyl sulfone, and bisphenol-A, to yield sulfonated poly ether sulfone (SPES). The resultant SPES polymer was blended with sPSEBPS followed by incorporation with an appropriate quantity of hBN. The physicochemical and structural properties of the membranes were studied in order to evaluate their compatibility with fuel cell applications. X-Ray photoelectron spectroscopy data validated the successful incorporation of the filler into the polymer matrix. Water absorption of the membranes was found in the range between 19.5 and 29.8%. The membrane loaded with 4.0 wt% of hBN showed the maximum ion-exchange capacity of 1.21 meq g-1, whereas the control sPSEBPS/SPES membrane was restricted to 0.48 meq g-1. The composite membrane loaded with hBN displayed higher thermal stability than that of the control sample. The sPSEBPS/SPES/hBN-4 composite membrane exhibited an ionic conductivity of 0.0329 S cm-1 at 30 °C. Overall, the experimental data of the prepared composite membranes revealed that the materials are potential candidates for fuel cells.

Efficient photocatalytic degradation of emerging ciprofloxacin under visible light irradiation using BiOBr/carbon quantum dot/saponite composite.

The use of visible-driven photocatalysts has fascinated attention as a capable and sustainable approach for wastewater remediation. In this work, BiOBr/carbon quantum dot (CQDs)/saponite composites (CQDs/Clay@BiOBr) were fabricated via hydrothermally using two different CQDs/Clay precursors (in-situ synthesis (IS) and physical mixing (PM)). The obtained products were characterized, and the photocatalytic performances of the prepared samples were evaluated in the photocatalytic decomposition of emerging ciprofloxacin (CIP) pharmaceutical waste. The highest CIP mineralization performance was achieved when a combination of BiOBr and CQDs/Clay (IS) with the appropriate proportion because the strong adhesion between CQDs and clay generate a great heterojunction in the composite. The stronger interaction of CQDs and better distribution of CQDs on the surface of clay in the CQDs/Clay (IS) enhanced the interaction of BiOBr and CQDs, and avoided the re-agglomeration of excess of CQDs on surface of BiOBr which reduce the active surface to receive the light and react with CIP. The ultrafast degradation rate of the optimized CQDs/Clay@BiOBr composite was better compared to others. The significant improvement in the CIP degradation efficiency of the CQDs/Clay@BiOBr composite was attributed to the excellent separation and transportation of photogenerated electrons and holes, as confirmed by photoluminescence, photocurrent density, and electrochemical impedance spectroscopy results. Moreover, the photocatalytic degradation mechanism of CIP in the CQDs/Clay@BiOBr composite was proposed based on the electronic states of each material in the composite and on a scavenger test. Thus, the proposed CQDs/Clay@BiOBr composite can be employed as a potential visible-light-driven photocatalyst for the decomposition of organic contaminants in wastewater.

Crystalline/amorphous nickel sulfide interface for high current density in alkaline HER: surface and volume confinement matters!

In this work, we demonstrate an interface on porous nickel foam (NN) between crystalline nickel sulfide and amorphous nickel sulfide (NNS/NNSx) adapting simple hydrothermal and facile electrodeposition processes, respectively. The developed electrocatalyst required a low overpotential of 15 mV to deliver a current density of 10 mA cm-2 and the interface intrinsically activates the electrocatalyst with an onset overpotential comparable to that of Pt in an alkaline hydrogen evolution reaction.

Anti-proliferative potentials of Aconitum heterophyllum Root Extract in Human Breast cancer (MDA-MB-231) cell lines-Genetic and Antioxidant enzyme approach.

Background: One of the most important research activities around the world is the screening of various plant components for novel anticancer medicines. The anticancer activities of Aconitum heterophyllum were studied in human breast cancer MDA-MB-231 cells in this study. Since tumorigenesis is thought to be the result of a series of progressive gene alterations, including oncogene activation and tumour suppressor gene inactivation, the expression of genes like p53, p21, STAT, and Bcl-2, which are thought to be important in tumorigenesis and cell death, was determined. In the present study there was an upregulation in the level expression of p53and p21 and down regulation in the expression of BCL2 and STAT. However, there is increase and decrease level of gene expression in Aconitum heterophyllum roots loaded Phyto-Niosomes (nEEAH), when compared to ethanolic root extract of Aconitum heterophyllum EEAH extract treated MDA-MB-231 cell lines. Methods: The enzymatic antioxidants such as CAT, SOD, GR, GST, and GPX as well as non-enzymatic antioxidants such as glutathione, Vitamin E and Vitamin C were estimated in the treated MDA-MB-231 cells at the end of incubation. The RT-PCR technique was performed to study the expression patterns of apoptotic genes such as p53 and p21 and anti-apoptotic genes BCL2 and STAT in the drug treated MDA-MB-231 cells. Results: In the present study there was a significant (p<0.05) increase in CAT and glutathione levels and a decrease in Vit C, Vit E and SOD, GR, GST, GPX levels in the untreated MDA-MB-231 cells. Increased apoptotic gene expression and decreased anti-apoptotic gene expression suggest the anti-proliferative nature of the drug extract was comparable to the doxorubicin the positive drug used in the present study. Conclusion: It can be concluded that the ethanolic extract of Aconitum heterophyllum roots loaded Phyto-Niosomes (nEEAH), when compared to ethanolic root extract of Aconitum heterophyllum EEAH extract treated MDA-MB-231 cell lines exert its anti-cancer activity by activating the apoptotic genes, suppressing anti-apoptotic genes as well as modulating the antioxidant enzymes.

Atomic-level investigation on significance of photoreduced Pt nanoparticles over g-C3 N4 /bimetallic oxide composites.

Designing an effective photocatalyst for solar-to-chemical fuel conversion presents significant challenges. Herein, g-C3 N4 nanotubes/CuCo2 O4 (CN-NT-CCO) composites decorated with platinum nanoparticles (Pt NPs) were successfully synthesized by chemical and photochemical reductions. The size distribution and location of Pt NPs on the surface of CN-NT-CCO composites were directly observed by TEM. Extended X-ray absorption fine structure (EXAFS) spectra of Pt L3-edge for the above composite confirmed establishment of Pt-N bonds at an atomic distance of 2.09 Šin the photoreduced Pt-bearing composite, which was shorter than in chemically reduced Pt-bearing composites. This proved the stronger interaction of photoreduced Pt NPs with the CN-NT-CCO composite than chemical reduced one. The H2 evolution performance of the photoreduced (PR) Pt@CN-NT-CCO (2079 µmol h-1 g-1 ) was greater than that of the chemically reduced (CR) Pt@CN-NT-CCO composite (1481 µmol h-1 g-1 ). The abundance of catalytically active sites and transfer of electrons from CN-NT to the Pt NPs to participate in the hydrogen evolution are the primary reasons for the improved performance. Furthermore, electrochemical investigations and band edge locations validated the presence of a Z-scheme heterojunction at the Pt@CN-NT-CCO interface. This work offers unique perspectives on the structure and interface design at the atomic level to fabricate high-performance heterojunction photocatalysts.

All-alike hollow nanotubes of g-C3N4 converting photons into fuel by splitting water.

In this article, we present a sapiential method for producing highly effective oxygen-containing CN with hierarchical porous hollow nanotubes (HTCN) using thermal polycondensation of oxalic acid-assisted supramolecular aggregates. As a result of the synergistic effect of spatial charge separation and optical absorption ability, HTCN outperforms pristine CN nanosheets (NSCN) in photocatalytic hydrogen production. This research will provide a novel cognitive perspective and understanding for constructing contemporary hydrogen production photocatalysts.

Sulfonated Poly Ether Sulfone Membrane Reinforced with Bismuth-Based Organic and Inorganic Additives for Fuel Cells.

This research work focuses on developing a robust polymer electrolyte membrane (PEM) with high proton efficiency toward proton exchange membrane fuel cells (PEMFCs). In this study, poly ether sulfone (PES) was sulfonated by chlorosulfonic acid to yield sulfonated poly ether sulfone (SPES) followed by incorporation with bismuth-based additives such as bismuth trimesic acid (BiTMA) and bismuth molybdenum oxide (Bi2MoO6). The composite membrane was thoroughly investigated for its structural and physicochemical properties such as FT-IR, SEM, TGA, contact angle, water uptake, oxidative stability, ion-exchange capacity, and swelling ratio. Incorporation of additives into the polymer was confirmed by XPS and XRD analysis. The proton conductance of the pristine SPES is 4.19 × 10-3 S cm-1, whereas that of the composite membrane SPES/BiTMA-10 is 10 × 10-3 S cm-1 and that of SPES/Bi2MoO6-15 is 7.314 × 10-3 S cm-1; both the composite membranes exhibit higher proton conductivity than the pristine SPES membrane. The physicochemical characteristics and impedance measurements of the electrolyte reported can be viable to the PEM membrane.

Nitridation-free preparation of bimetallic oxide-nitride bifunctional electrocatalysts for overall water splitting.

A novel one-pot surfactant-free synthesis is presented for designing bimetallic oxide-nitride electrocatalysts with tunable morphologies using metal salts and nitrogen-rich precursors. This innovative approach eliminates the need for a distinct nitridation process. Bifunctional electrode Co3O4/MoO3/MoxNy achieved a current density of 10 mA cm-2 while maintaining a cell voltage of 1.52 V, outperforming many bimetallic oxide-nitride catalysts in the scientific literature.

Tailoring Interfacial Physicochemical Properties in Cu2O-TiO2@rGO Heterojunction: Insights from EXAFS and Electron Trap Distribution Analysis.

In this study, a solution-based synthesis technique was utilized to produce Cu2O nanoparticles (NPs) on TiO2 nanofibers (TNF), which were then subsequently coated with reduced graphene oxide (rGO) nanosheets. In the absence of any cocatalyst, CTNF@rGO-3% composite displayed an ideal photocatalytic H2 evolution rate of 96 µmol g-1 h-1 under visible light irradiation, this was 10 times higher than that of pure TNF. At 420 nm, the apparent quantum efficiency of this composite reached a maximum of 7.18%. Kelvin probe force microscopy demonstrated the formation of an interfacial electric field that was oriented from CTNF to rGO and served as the driving force for interfacial electron transfer. The successful establishment of an intimate interface between CTNF@rGO facilitated the efficient transfer of charges and suppressed the rate of recombination of photogenerated electron-hole pairs, leading to a substantial enhancement in photocatalytic performance. X-ray photoelectron spectroscopy, photoluminescence spectra, and electrochemical characterization provide further confirmation that formation of a heterojunction between CTNF@rGO leads to an extension in the lifetimes of the photogenerated charge carriers. The experimental evidence suggests that a p-n heterojunction is the mechanism responsible for the significant photocatalytic activity observed in the CTNF@rGO composite during H2 evolution.

Synthesis, characterization, and application of MOF@clay composite as a visible light-driven photocatalyst for Rhodamine B degradation.

Metal Organic Frameworks (MOFs) with natural clay materials is a relatively new research avenue that appears to reduce high production costs and address the instability issues of pure MOFs. A novel MOF and natural clay composites of MOF@Sp_n (n = 1-4) were fabricated by the in situ precipitation of stable MOF, Zr6O4(OH)4 (ABDC)6 (where ABDC = 2-aminobenzene-1,4-dicarboxylic acid), over natural sepiolite (Sp) clay and used as a photocatalysts for elimination of organic dyes in aqueous media. The formation of MOF@Sp_n due to its strong electrostatic interactions between the positively charged MOF and the negatively charged sepiolite. Optimizing the Sp content in the composite strongly influenced the dispersibility, crystallinity of MOFs, resulting in progressively functional hybrid materials with an excellent optoelectronic properties. The composites lessened the shortcomings of the individual components and made them suitable as a visible light-active, highly efficient, standalone photocatalyst material that can degrade RhB.

Recent development on core-shell photo(electro)catalysts for elimination of organic compounds from pharmaceutical wastewater.

Pharmaceutical organics are a vital milestone in contemporary human research since they treat various diseases and improve the quality of human life. However, these organic compounds are considered one of the major environmental hazards after the conception, along with the massive rise in antimicrobial resistance (AMR) in an ecosystem. There are various biological and catalytic technologies existed to eliminate these organics in aqueous system with their limitation. Advanced Oxidation processes (AOPs) are used to decompose these pharmaceutical organic compounds in the wastewater by generating reactive species with high oxidation potential. This review focused various photocatalysts, and photocatalytic oxidation processes, especially core-shell materials for photo (electro)catalytic application in pharmaceutical wastewater decomposition. Moreover, we discussed in details about the design and recent developments of core shell catalysts and comparison for photocatalytic, electrocatalytic and photo electrocatalytic applications in pharmaceutical wastewater treatment. In addition, the mixture of inorganic and organic core-shell materials, and metal-organic framework-based core-shell catalysts discussed in detail for antibiotic degradation.

Hierarchical Na3V2(PO4)2F3 Microsphere Cathodes for High-Temperature Li-Ion Battery Application.

Sodium superionic conductor (NASICON)-structured Na3V2(PO4)2F3 cathode materials have received vast attention in the high-temperature storage performance due to their structural and thermal stability. Herein, hierarchical Na3V2(PO4)2F3 microspheres (NVPF-HMSs) consisting of nanocubes were designed by a one-pot facial solvothermal method. The hierarchical Na3V2(PO4)2F3 microsphere size is 2-3 µm, which is corroborated by FE-SEM and HR-TEM analyses. The NVPF-HMSs have been demonstrated as a cathode in Li-ion batteries at both low and elevated temperatures (25 and 55 °C, respectively). The NVPF-HMS cathode in a Li-ion cell exhibits reversible capacities of 119 mA h g-1 at 0.1 C and 85 mA h g-1 at 1 C with an 82% retention after 250 cycles at 25 °C. At elevated temperatures, the NVPF-HMS cathode exhibits a superior capacity of 110 mA h g-1 at 1 C along with a retention of 90% after 150 cycles at 55 °C. Excellent capacity and cyclability were achieved at 55 °C due to its hierarchical morphology with a robust crystal structure, low charge-transfer resistance, and improved ionic diffusivity. The Li-ion storage performance of the NVPF-HMS cathode material at elevated temperatures was analyzed for the first time to understand the high-temperature storage property of the material, and it was found to be a promising candidate for elevated-temperature energy storage applications.

Recent development of organic-inorganic hybrid photocatalysts for biomass conversion into hydrogen production.

Over the last few years, photocatalysis using solar radiation has been explored extensively to investigate the possibilities of producing fuels. The production and systematic usage of solar fuels can reduce the use of fossil-based fuels, which are currently the primary source for the energy. It is time for us to exploit renewable sources for our energy needs to progress towards a low-carbon society. This can be achieved by utilizing green hydrogen as the future energy source. Solar light-assisted hydrogen evolution through photocatalytic water splitting is one of the most advanced approaches, but it is a non-spontaneous chemical process and restricted by a kinetically demanding oxidation evolution reaction. Sunlight is one of the essential sources for the photoreforming (PR) of biomass waste into solar fuels, or/and lucrative fine chemicals. Hydrogen production through photoreforming of biomass can be considered energy neutral as it requires only low energy to overcome the activation barrier and an alternate method for the water splitting reaction. Towards the perspective of sustainability and zero emission norms, hydrogen production from biomass-derived feedstocks is an affordable and efficient process. Widely used photocatalyst materials, such as metal oxides, sulphides and polymeric semiconductors, still possess challenges in terms of their performance and stability. Recently, a new class of materials has emerged as organic-inorganic hybrid (OIH) photocatalysts, which have the benefits of both components, with peculiar properties and outstanding energy conversion capability. This work examines the most recent progress in the photoreforming of biomass and its derivatives using OIHs as excellent catalysts for hydrogen evolution. The fundamental aspects of the PR mechanism and different methods of hydrogen production from biomass are discussed. Additionally, an interaction between both composite materials at the atomic level has been discussed in detail in the recent literature. Finally, the opportunities and future perspective for the synthesis and development of OIH catalysts are discussed briefly with regards to biomass photo-reforming.

The influence of heterostructured TiO2/ZnO nanomaterials for the removal of azo dye pollutant.

In recent times, there has been an inspired research on combining semiconducting metal oxides for improved industrial applications. Significantly, wastewater removal is concerned and the researchers are finding new methodologies for removing azo dyes that possess a high level of carcinogenic effects. In this connection, this work investigates the photocatalytic activity of synthesized TiO2/ZnO nanocomposite irradiated under UV and visible light. The application of the work involves the removal of methylene blue (MB) dye solution. Initial work begins with the novel synthesis of TiO2/ZnO coupled system by integrated sol-gel and thermal decomposition methods. Then, various characterization techniques brought out the existing properties of the prepared TiO2/ZnO catalyst. The X-ray diffraction measurements showed the assorted tetragonal and hexagonal structures. The spherical shape mixed with hexagonal shaped particles were perceived via transmission electron microscopy (TEM). Besides, from photoluminescence spectrum (PL) results, the TiO2/ZnO coupled system displayed slowing down of charge recombination, because of the intermediate states that helps in intensifying the photocatalytic activity. The dual absorption bands corresponding to UV region were deep-rooted from UV-vis spectroscopy. Further, the valuable application of the catalyst in removing methylene blue (MB) dye under both UV and visible light was carried out. The catalyst had displayed 90% of degradation within 40 min under UV light conditions. The other hand, visible light illumination of the catalyst provides divergent results as it possess lesser light absorption. Therefore, this catalyst was unable to yield visible light photocatalytic activity. Hence, this captivating research would bring the wastewater treatment progression using UV light.

A critical and recent developments on adsorption technique for removal of heavy metals from wastewater-A review.

This review provides a quantitative description of the nano-adsorbent processing and its viability against wastewater detoxification by extracting heavy metal ions. The impact of nano-adsorbent functionalities on specific essential attributes such as the surface area, segregation, and adsorption capacity were comprehensively evaluated. A detailed analysis has been presented on the characteristics of nanomaterials through their limited resistance to adsorb some heavy metal ions. Experimental variables such as the adsorbent dosage, pH, substrate concentration, response duration, temperature, and electrostatic force that influence the uptake of metal ions have been studied. Besides, separate models for the adsorption kinetics and isothermal adsorption have been investigated to understand the mechanism behind adsorption. Here, we reviewed the different adsorbent materials with nano-based techniques for the removal of heavy metals from wastewater and especially highlighted the nano adsorption technique. The influencing factors such as pH, temperature, dosage time, sorbent dosage, adsorption capacities, ion concentration, and mechanisms related to the removal of heavy metals by nano composites are highlighted. Lastly, the application potentials and challenges of nano adsorption for environmental remediation are discussed. This critical review would benefit engineers, chemists, and environmental scientists involved in the utilization of nanomaterials for wastewater treatment.