Comparative analysis of the equilibrium, kinetics, and characterization of the mechanism of rapid adsorption of Congo red on nano-biosorbents based on agricultural waste in industrial effluents.

This study aims to remove Congo red dye from industrial effluent using economical agriculturally-based nano-biosorbents like magnetic orange peel, peanut shells, and tea waste. The nano-biosorbents were characterized by various analytical techniques like SEM, FT-IR, BET and XRD. The highest adsorption capacity was obtained under the following ideal conditions: pH = 6 (orange peel and peanut shells), pH = 3 (tea waste), and dosages of nano-biosorbents with varying timeframes of 50 min for tea waste and peanut shells and 30 min for orange peel. The study found that tea waste had the highest removal rate of 94% due to its high porosity and responsible functional groups, followed by peanut shells at 83% and orange peel at 68%. The Langmuir isotherm model was found to be the most suitable, with R2 values of 0.99 for tea waste, 0.92 for orange peel, and 0.71 for peanut shells. On the other hand, a pseudo-second-order kinetic model was very feasible, showing an R2 value of 0.99 for tea waste, 0.98 for peanut shells and 0.97 for orange peel. The significance of the current study lies in its practical application, enabling efficient waste management and water purification, thereby preserving a clean and safe environment.

Flow injection assays for NADH and ethanol using photosensitized rose bengal and luminol-copper (II) chemiluminescence system.

The online photoreaction of the rose bengal photosensitized luminol-copper (II) chemiluminescence (CL) system was used for the determination of ß-nicotinamide adenine dinucleotide (NADH) and ethanol (EtOH) in pharmaceutical formulations combined with a flow injection technique. NADH can significantly enhance the CL emission of the reaction. For EtOH, alcohol dehydrogenase in soluble form was utilized in the presence of nicotinamide adenine dinucleotide resulting in NADH production. The limit of detection (3σ blank, 𝑛 = 3) of 4.0 × 10-8 and 2.17 × 10-5  M, and linear range 1.3 × 10-7 to 2.5 × 10-5  M (R2  = 0.9998, n = 6) and 0.11-2.17 × 10-3  M (R2  = 0.9996, n = 6) were obtained for NADH and EtOH respectively. The injection rate was 100 h-1 with a relative standard deviation (n = 3) of 1.5-4.8% in the range studied for both analytes. The procedure was satisfactorily applied to pharmaceutical formulations with recoveries in the range 91.6 ± 3.0% to 110 ± 2.0% for NADH and 88 ± 3.0% to 95.4 ± 4.0% for EtOH. The results obtained were very consistent and did not differ considerably from the reported approaches at a 95% confidence limit. The possible mechanism of the CL reaction is also explained briefly.

Flow-injection determination of manganese (II) using surfactant enhanced diperiodatonickelate (IV)-rhodamine 6G chemiluminescence.

Chemiluminescence (CL) of the rhodamine 6-G-diperiodatonickelate (IV) (Rh6-G-Ni(IV) complex) in the presence of Brij-35 was examined in an alkaline medium and implemented using flow-injection analysis to analyze Mn(II) in natural waters. Brij-35 was identified as the surfactant of choice that enhanced CL intensity by about 62% of the reaction. The calibration curves were linear in the range 1.7 × 10-3 - 0.2 (0.9990, n = 7) and 8.0 × 10-4 - 0.1 µg ml-1 (0.9990, n = 7) with limits of detection (LODs) (S:N = 3) of 5.0 × 10-4 and 2.4 × 10-4 µg ml-1 without and with using an in-line 8-hydroxyquinoline (8-HQ) resin mini-column, respectively. The sample throughput and relative standard deviation were 200 h-1 and 1.7-2.2% in the range studied respectively. Mn(II) concentrations in certified reference materials and natural water samples was successfully determined. A brief discussion about the possible CL reaction mechanism is also given. In addition, analysis of V(III), Cr(III) and Fe(II) was also performed without and with using an in-line 8-HQ column and selective elution of each metal ion was achieved by adjusting the pH of the sample carrier stream with aqueous HCl solution.

Environmental risk assessment of diclofenac residues in surface waters and wastewater: a hidden global threat to aquatic ecosystem.

Pharmaceuticals are chemical compounds employed as medicinal drugs. They have severe physic-chemical properties which make them destructive for non-target species. Consequently, their continuous addition in the environment may pose hazardous effects. Among these, diclofenac (DCF), a non-steroidal anti-inflammatory drug (NSAID), is extensively used in Pakistan which may lead to its accumulation in both terrestrial and aquatic environment. Present study aims to assess the presence and concentration of pharmaceutically active drug (DCF) in surface water and wastewater of twin cities of Pakistan (Rawalpindi and Islamabad). For this purpose, a validated high-performance liquid chromatography (HPLC) method was adopted involving solid-phase extraction procedure. Wastewater samples were collected from various sites of Rawalpindi and Islamabad. Results of HPLC analysis revealed that DCF was extant with considerably high concentration, not only in wastewater but also in surface water samples. Concentrations as high as 216 µg L-1 was detected in Rawat industrial area and low as 8 µg L-1 was detected in dairy farm wastewater samples collected from Taramri. However, maximum DCF levels in residential wastewater and hospital wastewater were detected to be 105 µg L-1 and 34 µg L-1, respectively. Moreover, the highest detected level (116 µg L-1) was found in surface water of Sawan River. Further, results of ecological risk assessment revealed its possible toxic effects of DCF on various aquatic organisms.

Synthesis of 2-nitro aniline derivative of 3, 4, 5-trihydroxybenzoic acid, its metal complexes, characterization and bioassay.

Present research work discloses new and novel synthesis of metal complexes (Fe, Cu, Zn, Sb and Sn) of 3, 4, 5-trihydroxybenzoic acid derivative containing aniline moiety with substitution at C-7 position of 3, 4, 5-trihydroxybenzoic acid in order to enhance its biological activities by coupling therapeutic values of transition metals as well. In vitro antibacterial and antifungal activities of these compounds has been performed by using agar diffusion method against different bacterial and fungal strains. The free radical scavenging assay was performed by using 2, 2-diphenyl-1-picryl-hydrazyl (DPPH). Cytotoxic action of compounds was assessed by utilizing the standard MTT (3-[4, 5-dimethylthiazole-2-yl]-2, 5-diphenyl-tetrazolium bromide) colorimetric assay. The structure of newly synthesized complexes were confirmed by using IR and 1HNMR spectral analysis.

Nanotextured Spikes of α-Fe2O3/NiFe2O4 Composite for Efficient Photoelectrochemical Oxidation of Water.

We demonstrate for the first time the application of p-NiFe2O4/n-Fe2O3 composite thin films as anode materials for light-assisted electrolysis of water. The p-NiFe2O4/n-Fe2O3 composite thin films were deposited on planar fluorinated tin oxide (FTO)-coated glass as well as on 3D array of nanospike (NSP) substrates. The effect of substrate (planar FTO and 3D-NSP) and percentage change of each component (i.e., NiFe2O4 and Fe2O3) of composite was studied on photoelectrochemical (PEC) water oxidation reaction. This work also includes the performance comparison of p-NiFe2O4/n-Fe2O3 composite (planar and NSP) devices with pure hematite for PEC water oxidation. Overall, the nanostructured p-NiFe2O4/n-Fe2O3 device with equal molar 1:1 ratio of NiFe2O4 and Fe2O3 was found to be highly efficient for PEC water oxidation as compared with pure hematite, 1:2 and 1:3 molar ratios of composite. The photocurrent density of 1:1 composite thin film on planar substrate was equal to 1.07 mA/cm2 at 1.23 VRHE, which was 1.7 times higher current density as compared with pure hematite device (0.63 mA/cm2 at 1.23 VRHE). The performance of p-NiFe2O4/n-Fe2O3 composites in PEC water oxidation was further enhanced by their deposition over 3D-NSP substrate. The highest photocurrent density of 2.1 mA/cm2 at 1.23 VRHE was obtained for the 1:1 molar ratio p-NiFe2O4/n-Fe2O3 composite on NSP (NF1-NSP), which was 3.3 times more photocurrent density than pure hematite. The measured applied bias photon-to-current efficiency (ABPE) value of NF1-NSP (0.206%) was found to be 1.87 times higher than that of NF1-P (0.11%) and 4.7 times higher than that of pure hematite deposited on FTO-coated glass (0.044%). The higher PEC water oxidation activity of p-NiFe2O4/n-Fe2O3 composite thin film as compared with pure hematite is attributed to the Z-path scheme and better separation of electrons and holes. The increased surface area and greater light absorption capabilities of 3D-NSP devices result in further improvement in catalytic activities.

Adsorption Kinetics of Malachite Green and Methylene Blue from Aqueous Solutions Using Surfactant-modified Organoclays.

The main objective of this research is to study the adsorption behaviour of malachite green and methylene blue dyes onto the surfactant modified natural clays. The results of SEM, XRD, IR, and thermal analysis confirms the intercalation of organic moiety in to the clay. The adsorption results show that pseudo-first order kinetics best fitted for both the dyes adsorbed on organo-clay. The data also reveals that both dyes are in a good agreement with Langmuir isotherm in both types of modified clays. The value of separation factor, RL, from Langmuir equation and Freundlich constant, n, give an indication of favourable adsorption. The maximum adsorption capacity qm based on Langmuir model was found to be 294-303 mg/g at 25 °C, is in good agreement with the experimental values.

MXene boosted MOF-derived cobalt sulfide/carbon nanocomposites as efficient bifunctional electrocatalysts for OER and HER.

The development of effective bifunctional electrocatalysts that can realize water splitting to produce oxygen and hydrogen through oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is still a great challenge to be addressed. Herein, we report a simple and versatile approach to fabricate bifunctional OER and HER electrocatalysts derived from ZIF67/MXene hybrids via sulfurization of the precursors in hydrogen sulfide gas atmosphere at high temperatures. The as-prepared CoS@C/MXene nanocomposites were characterized using a series of technologies including X-ray diffraction, gas sorption, scanning electronic microscopy, transmission electronic microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. The synthesized CoS@C/MXene composites are electrocatalytically active in both HER and OER, and the CSMX-800 composite displayed the highest electrocatalytic performance towards OER and HER among all the produced samples. CSMX-800 exhibited overpotentials of 257 mV at 10 mA cm-2 for OER and 270 mV at 10 mA cm-2 for HER. Moreover, it also possesses small Tafel slope values of 93 mV dec-1 and 103 mV dec-1 for OER and HER, respectively. The enhanced electrocatalytic performance of the MXene-containing composites is due to their high surface area, enhanced conductivity, and faster charge transfer. This work demonstrated that CoS@C/MXene based electrocatalyst has great potential in electrochemical water splitting for hydrogen production, thus reducing carbon emissions and protecting the environment.

High performance electrochemical CO2 reduction over Pd decorated cobalt containing nitrogen doped carbon.

Efficient electrocatalytic CO2 reduction reaction (eCO2RR) to various products, such as carbon monoxide (CO), is crucial for mitigating greenhouse gas emissions and enabling renewable energy storage. In this article, we introduce Pd nanoparticles which are deposited over in-house synthesized nitrogen doped tubular carbon (NC) whose ends are blocked with cobalt oxide (CoOx). This composite material is denoted as Pd@CoOx/NC. Among the series of synthesized electrocatalysts, the optimum ratio (Pd@CoOx/NC1) within this category exhibits exceptional performance, manifesting an 81% faradaic efficiency (FE) for CO generation which was quantitatively measured using a gas chromatograph. This remarkable efficiency can be attributed to several scientific factors. Firstly, the presence of Pd nanoparticles provides active sites for CO2 reduction. Secondly, the NC offer enhanced electrical conductivity and facilitate charge transfer during the reaction. Thirdly, the CoOx capping at the ends of the NC serves to stabilize the catalyst, favoring the formation of CO. The remarkable selectivity of the catalyst is further confirmed by the qualitative CO detection method using PdCl2 strips. Pd@CoOx/NC1 exhibits a high current density of 55 mA cm-2 and a low overpotential of 251 mV, outperforming Pd decorated multiwalled carbon nanotubes (Pd@MWCNTs) which shows a higher overpotential of 481 mV. Pd@CoOx/NC1 shows long-term stability at different potentials and rapid reaction kinetics. These findings highlight Pd@CoOx/NC1 as promising CO2 reduction catalysts, with implications for sustainable energy conversion techniques.

Synthesis of 2-aminothiazole sulfonamides as potent biological agents: Synthesis, structural investigations and docking studies.

A simplified synthetic approach involving sulfonylation followed by amino group alkylation produced new 2-aminothiazole derivatives. UV/Vis, infrared, and NMR spectroscopies confirmed their structures. Compounds 36, 22, 34, and 35 showed strong inhibition against Jack bean and Bacillus Pasteurii urease, with IC50 values from 14.06 to 20.21 µM/mL. Compounds 20, 26, 21, 29, 30, 31, and 32 exhibited potent inhibitory effects against α-glucosidase and α-amylase, with IC50 values between 20.34 and 37.20 µM/mL. Compounds 33, 26, and 27 demonstrated potent DPPH scavenging, with IC50 values around 34.4-39.2 µM/mL. FMO analysis showed compounds 21, 22, 24, and 25 having parallel aromatic ring systems due to π cloud interactions, while compounds 32 and 38 had distinct electronic density distributions. Compound 22 had HOMO and LUMO energy gaps of 5.805 eV, with bromo and fluoro substitutions in compounds 21 and 24 slightly increasing the gaps to 6.089 eV and 6.078 eV, respectively. Nitro groups in compounds 25 and 32 reduced the gaps to 0.384 eV and 1.187 eV. All compounds demonstrated high gastrointestinal absorption, non-permeability to the blood-brain barrier, and optimal skin permeation (Log Kp between -5.83 and -6.54 cm/s). Compounds 22, 24, and 38 had promising QED scores of 0.719, 0.707, and 0.860, respectively, with synthetic accessibility scores from 2.057 to 2.517. ADMET predictions indicated minimal toxicity, cardiovascular safety, and significant inhibitory potential for CYP enzymes. Strong in silico binding affinities (binding energies -5.75 to -7.63 kcal/mol) and metabolic stability suggest these derivatives are promising candidates for further drug development.

Recent trends in wastewater treatment by using metal-organic frameworks (MOFs) and their composites: A critical view-point.

Respecting the basic need of clean and safe water on earth for every individual, it is necessary to take auspicious steps for waste-water treatment. Recently, metal-organic frameworks (MOFs) are considered as promising material because of their intrinsic features including the porosity and high surface area. Further, structural tunability of MOFs by following the principles of reticular chemistry, the MOFs can be functionalized for the high adsorption performance as well as adsorptive removal of target materials. However, there are still some major concerns associated with MOFs limiting their commercialization as promising adsorbents for waste-water treatment. The cost, toxicity and regenerability are the major issues to be addressed for MOFs to get insightful results. In this article, we have concise the current strategies to enhance the adsorption capacity of MOFs during the water-treatment for the removal of toxic dyes, pharmaceuticals, and heavy metals. Further, we have also discussed the role of metallic nodes, linkers and associated functional groups for effective removal of toxic water pollutants. In addition to conformist overview, we have critically analyzed the MOFs as adsorbents in terms of toxicity, cost and regenerability. These factors are utmost important to address before commercialization of MOFs as adsorbents for water-treatment. Finally, some future perspectives are discussed to give directions for potential research.

Comparative study of laterite and bentonite based organoclays: implications of hydrophobic compounds remediation from aqueous solutions.

Four cost effective organoclays were synthesized, characterized, and studied for the sorption of hydrophobic compounds (edible oil/grease and hydrocarbon oil) from aqueous solutions. Organoclays were prepared by cation exchange reaction of lattice ions (present onto the surface of laterite and bentonite clay minerals) with two surfactants, hexadecyl trimethyl ammonium chloride (HDTMA-Cl) and tetradecyl trimethyl ammonium bromide (TDTMA-Br). Fourier transform infrared spectroscopy and scanning electron microscopy were used for the characterization of synthesized organoclays. It was found that the amount of surfactant loading and the nature of the surfactant molecules used in the syntheses of organoclay strongly affect the sorption capacity of the clay mineral. Further, it was found that both the laterite and bentonite based organoclays efficiently removed the edible and hydrocarbon oil content from lab prepared emulsions; however, the adsorption capacity of clay mineral was greatly influenced by the nature of hydrophobic compounds as well.

Linker Engineering of Sandwich-Structured Metal-Organic Framework Composites for Optimized Photocatalytic H2 Production.

While the microenvironment around catalytic sites is recognized to be crucial in thermocatalysis, its roles in photocatalysis remain subtle. In this work, a series of sandwich-structured metal-organic framework (MOF) composites, UiO-66-NH2 @Pt@UiO-66-X (X means functional groups), is rationally constructed for visible-light photocatalytic H2 production. By varying the ─X groups of the UiO-66-X shell, the microenvironment of the Pt sites and photosensitive UiO-66-NH2 core can be simultaneously modulated. Significantly, the MOF composites with identical light absorption and Pt loading present distinctly different photocatalytic H2 production rates, following the ─X group sequence of ─H > â”€Br > â”€NA (naphthalene) > â”€OCH3  > â”€Cl > â”€NO2 . UiO-66-NH2 @Pt@UiO-66-H demonstrates H2 production rate up to 2708.2 µmol g-1  h-1 , ≈222 times that of UiO-66-NH2 @Pt@UiO-66-NO2 . Mechanism investigations suggest that the variation of the ─X group can balance the charge separation of the UiO-66-NH2 core and the proton reduction ability of Pt, leading to an optimal activity of UiO-66-NH2 @Pt@UiO-66-H at the equilibrium point.

Three-dimensional Ni4O4-cubane metal-organic framework as a high-performance electrocatalyst for urea oxidation.

The urea oxidation reaction (UOR) is considered to be a replacement of the sluggish anodic oxygen evolution reaction (OER) in overall water-splitting. A three-dimensional (3D) nickel-containing metal-organic framework {[NiII 2(pdaa)(OH)2(H2O)] n (MOF 1) (where, H2pdaa = 1,4-phenylene diacetic acid) was investigated as a robust and highly efficient electrocatalyst for the UOR. MOF 1 comprised 1D nickel(ii) chains crosslinked through Ni4O4 cubane units to form a 3D extended network. Dangling Ni⋯OH- groups were exposed in the MOF 1 structure, and could act as active catalytic centers for the UOR. MOF 1 required a very small onset potential of 1.18 V for urea oxidation in KOH (1 M) and urea (0.33 M) and had a low Tafel slope of 38.8 mV dec-1 (in contrast to 1.84 V for the oxygen evolution reaction). The overpotential required to attain a catalytic current density of 10 mA cm-2 was 1.24 V, which is much lower than that for many materials. Controlled potential electrolysis, powder X-ray diffraction, and X-ray photoelectron spectroscopy affirmed the physicochemical integrity of the catalyst over a 17 h test reaction. This work not only addresses the problem of urea contamination, it also helps to utilize it in an energy-conversion process.

Facile Synthesis of a Novel Ni-WO3@g-C3N4 Nanocomposite for Efficient Oxidative Desulfurization of Both Model and Real Fuel.

The current study comprises the successful synthesis of a Ni-WO3@g-C3N4 composite as an efficient and recoverable nanocatalyst for oxidative desulfurization of both model and real fuel oils. The physiochemical characterization of the synthesized composite was confirmed via Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. SEM results showed that Ni-WO3 particles were well-decorated on the g-C3N4 surface with an interesting morphology as appeared on the surface like spherical particles. The obtained findings revealed that 97% dibenzothiophene (DBT) removal can be achieved under optimized conditions (0.1 g of the catalyst, 1 mL of an oxidant, 100 mg/L DBT-based model fuel, a time duration of 180 min, and a temperature of 40 °C). Additionally, the catalytic activity for real fuel was also investigated in which 89.5 and 91.2% removal efficiencies were achieved for diesel and kerosene, respectively, as well as fuel properties following ASTM specifications. A pseudo first-order kinetic model was followed well for this reaction system, and the negative value of ΔG was due to the spontaneous process. Additionally, the desulfurization study was optimized via a response surface methodology (RSM/Box-Behnken design) for predicting optimum removal of sulfur species by drawing three-dimensional RSM surface plots. The Ni-WO3@g-C3N4 proved to be a promising catalyst for desulfurization of fuel oil by exhibiting reusability of five times with no momentous decrease in efficiency.

Perovskite LaNiO3/Ag3PO4 heterojunction photocatalyst for the degradation of dyes.

Pristine lanthanum nickelate (LaNiO3), silver phosphate (Ag3PO4) and perovskite lanthanum nickelate silver phosphate composites (LaNiO3/Ag3PO4) were prepared using the facile hydrothermal method. Three composites were synthesized by varying the percentage of LaNiO3 in Ag3PO4. The physical properties of as-prepared samples were studied by powder X-ray diffraction (pXRD), Fourier-transform infrared (FT-IR), Scanning electron microscopy (SEM) and Energy-dispersive X-ray (EDX). Among all synthesized photocatalysts, 5%LaNiO3/Ag3PO4 composite has been proved to be an excellent visible light photocatalyst for the degradation of dyes i.e., rhodamine B (RhB) and methyl orange (MO). The photocatalytic activity and stability of Ag3PO4 were also enhanced by introducing LaNiO3 in Ag3PO4 heterojunction formation. Complete photodegradation of 50 mg/L of RhB and MO solutions using 25 mg of 5%LaNiO3/Ag3PO4 photocatalyst was observed in just 20 min. Photodegradation of RhB and MO using 5%LaNiO3/Ag3PO4 catalyst follows first-order kinetics with rate constants of 0.213 and 0.1804 min-1, respectively. Perovskite LaNiO3/Ag3PO4 photocatalyst showed the highest stability up to five cycles. The photodegradation mechanism suggests that the holes ( h +) and superoxide anion radicals O 2 • - plays a main role in the dye degradation of RhB and MO.

Silane-Grafted MXene (Ti3C2T X ) Membranes for Enhanced Water Purification Performance.

The current communication describes the modifications of MXene (Ti3C2T x ) with silane grafting reaction for membrane preparation for enhanced water purification. The MXene was successfully grafted with n-octadecyltrichlorosilane (MODCS), n-octyltrichlorosilane (MNOCS), and triphenylchlorosilane (MTPCS) in order to make a hydrophobic MXene that could be able to bind with the organic matrix/polymers. The modified MXenes were transformed into thin membranes by forming an MXene/polyvinyl alcohol (PVA) composite over a filter paper support, that is, MCE (mixed cellulose ester filter paper). MXene membranes were also formed without the MCE support by using PVA and glutaraldehyde (PVA/GA) where GA was used as a cross-linker to stabilize PVA and make it water-resistant. The conditions of membrane formation were optimized to investigate optimum compatible conditions with the modified materials. The resulting membranes were tested for the removal of various organic pollutants that included mesitylene (or trimethylbenzene); polyaromatic hydrocarbons (chrysene, as a model); biphenyl; bisphenol A; benzene, toluene, ethylbenzene, and styrene; methylene blue; and Sudan II dyes. The MTPCS PVA/GA cross-linked membrane showed the best results for a pollutant removal efficiency up to 98%. Overall, all six types of membranes showed the removal efficiency in the range of 52-98%. It was observed that the membrane exhibits reusability up to five cycles.

Linker engineering in metal-organic frameworks for dark photocatalysis.

Dark reactions featuring continuous activity under light off conditions play a critical role in natural photosynthesis. However, most artificial photocatalysts are inactive upon the removal of the light source, and the artificial photocatalysts with dark photocatalysis abilities have been rarely explored. Herein, we report a Ti-based metal-organic framework (MOF), MIL-125, exhibiting the capability of dark photocatalytic hydrogen production. Remarkably, the introduction of different functional groups onto the linkers enables distinctly different activities of the resulting MOFs (MIL-125-X, X = NH2, NO2, Br). Dynamic and thermodynamic investigations indicate that the production and lifetime of the Ti3+ intermediate are the key factors, due to the electron-donating/-withdrawing effect of the functional groups. As far as we know, this is the first report on dark photocatalysis over MOFs, providing new insights into the storage of irradiation energy and demonstrating their great potential in dark photocatalysis due to the great MOF diversity.

Recent progress in use of MXene in perovskite solar cells: for interfacial modification, work-function tuning and additive engineering.

The use of perovskites in photovoltaic and related industries has achieved tremendous success over the last decade. However, there are still obstacles to overcome in terms of boosting their performance and resolving stability issues for future commercialization. The introduction of a new 2D material of halide perovskites is now the key advancement in boosting the solar energy conversion efficiency. The implication of a new 2D material (MXene) in perovskite solar cells has been initiated since its first report in 2018, showing excellent transparency, electrical conductivity, carrier mobility, superior mechanical strength, and tunable work function. Based on distinctive features at the hetero-interface, halide perovskite and MXene heterostructures (HPs/Mx) have recently exhibited exceptional improvements in both the performance and stability of perovskite solar cells. Furthermore, the wide families of HPs and MXene materials allow playing with the composition and functionalities of HP/Mx interfaces by applying rational designing and alterations. In this review a comprehensive study of implementing MXenes in perovskite solar cells is presented. First, the implementation of MXenes in perovskites as an additive, and then in charge extraction layers (HTL/ETL), is described in detail. It is worth noting that still only Ti3C2Tx, Nb2CTx,V2CTx MXene is being incorporated into perovskite photovoltaics. Finally, the present obstacles in the use of MXenes in PSCS are discussed, along with the future research potential. This review is expected to provide a complete and in-depth description of the current state of research and to open up new opportunities for the study of other MXenes in PSCs.

Exploration of microplastic pollution with particular focus on source identification and spatial patterns in riverine water, sediment and fish of the Swat River, Pakistan.

Microplastics (MPs) have been reported as an emerging xenobiotic organic pollutant in freshwater ecosystems and a universal hazard for ecosystems because of the rapid increase in global demand. The present study was conducted to explore MPs' occurrence, abundance and spatial distribution in sediment, water and Schizothorax plagiostomus samples, collected from the Swat River. ATR-FTIR spectroscopy was used for chemical characterization of visually identified MPs by using standard protocols such as digestion using H2O2, density separation using ZnCl2, vacuum filtration with borosilicate glass micro filter papers and digital microscopy using a stereomicroscope connected with a camera. Range of mass abundance of identified MPs in river sediments, river water, tributaries sediment and tributary water was found to be 0.6-2.5 mg kg-1, 0.7-3.8 mg L-1, 0.9-4.5 mg kg-1 and 0.6-1.1 mg L-1 respectively. Meanwhile, in Schizothorax plagiostomus digestive tracts samples, it was 0.6-1.9 mg per fish. Numeric abundance of MPs in all matrices was found to be tributary sediment (202 items per kg) > river water (192 items per L) > river sediment (182 items per kg) > fish (153 items per fish) > tributary water (92 items per L). MPs identified on the basis of morphology in all matrices were found to be fragments > fibers > pellets > films > foams. MPs were dominant in all urban stations while their spatial distribution along with the study site was heterogeneous due to the surroundings such as tourist spots, hydrodynamic conditions, and proximity to urban areas, plastic industries and due to recharge by the highly contaminated tributaries. The MPs identified on the basis of size dimensions show that S1 (0.5-1 mm) in all matrices was highest while S2 (1-5 mm) was the lowest. Primary source MPs identified were fibers, films, fragments and foams particles while secondary sources were pellets. Results of ATR-FTIR showed that PE was the most common plastic type identified in all samples followed by PVC, PET, PP and PS. This is the first study exploring the MPs' occurrence, numeric and mass abundance and spatial distribution in the SR ecosystem. The present study may be a valuable reference for better understanding the MPs' pollution in Pakistan. The findings of the present study can help to identify the potential sources (i.e., primary and secondary) of MPs to improve waste management in the Swat District and model the transport fluxes of these microplastics in other rivers using water quality parameters and basin characteristics.