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Organic dye pollutants present in wastewater pose a significant global challenge. Among pollutants, the synthetic dye Rhodamine B (RB) stands out due to its non-biodegradable nature and associated neurotoxic, carcinogenic, and respiratory irritant properties. Extensive research has been conducted on the efficacy of adsorption and photodegradation techniques for the removal of RB from wastewater. While adsorption and advanced oxidation processes (AOPs) have gained considerable attention for their effectiveness in recent years, the underlying behaviors and mechanisms of these technologies remain incompletely understood. Therefore, a comprehensive summary of recent research progress in this domain is imperative to clarify the basics and present the up-to-date achievements.This review provides an in-depth exploration of the fundamentals, advancements, and future trajectories of RB wastewater treatment technologies, mainly encompassing adsorption and photodegradation. This work starts with a general introduction of outlining the sources, toxicity, and diverse applicable removal strategies. Subsequently, it thoroughly examines crucial techniques within non-photochemical, photochemical, and adsorption technologies, such as UV light assisted AOP, catalyst assisted AOP, ozonation, Fenton system, electrochemical AOP, and adsorption technology. The primary objective is to furnish a broad overview of these techniques, elucidating their effectiveness, limitations, and applicability. Following this, the review encapsulates state-of-the-art computational simulations pertaining to RB adsorption and interactions with clays and other adsorbents. Lastly, it delves into column adsorption of RB dye, and elucidates various influencing factors, including bed height, feed concentration, pollutant (RB) feeding or flow rate, and column regeneration. This panoramic review aims to provide valuable insights into suitable techniques, research gaps, and the applicability of non-photochemical, photochemical, and adsorption technologies in the treatment of wastewater containing RB dye.

This study examines the complex dynamics of an incompressible, electrically conducting third-grade fluid (TGF) flow through a vertical micro-channel that is filled with porous media. The research utilizes asymmetrical convective cooling, a transverse magnetic field, and exothermic reactions to introduce a comprehensive model. The viscosity of the fluid, which is determined by the Naham-type law, changes significantly with temperature. Additionally, the convective heat transfer rates, which govern the asymmetric convective cooling at the surfaces of the micro-channel, are modeled using Newton's law of cooling, and Modified Darcy law is used to address the porous medium effect. To solve the complex system of nonlinear partial differential equations, we employ computational solutions derived from reliable and efficient finite difference methods (FDM). The method is tested for different time-steps and mesh sizes and it is found that the algorithms reliably produce the same results. Our investigation includes an evaluation of both spatial and temporal convergence of the FDM scheme. The study present qualitative discussions of graphical results, that highlight the impact of various flow parameters integrated into the system. The velocity and temperature profiles increases for higher values of thermal Grashoff number Gr and Reynolds number Re while opposite effect is noticed for increasing values of Hartman number M.

Green synthesis of metal nanoparticles (NPs) has received extensive attention over other conventional approaches due to their non-toxic nature and more biocompatibility. Herein we report gold and silver NPs (AuNPs@AV and AgNPs@AV) prepared by employing a green approach using crude extract of Aconitum violaceum Jacquem. ex Stapf. The synthesized NPs were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX), X-ray Diffraction (XRD), UV/Visible spectroscopy, Fourier Transform Infrared (FTIR), X-ray Photoelectron Spectroscopy (XPS), and Zeta Potential. Morphological analysis showed spherical and triangular shapes of the NPs with average size of

Based on the versatile nature and applications of Carbon foam (CF), up to now many attempts were performed to improve the structure and properties of CF by incorporating various additives in the CF matrix. But these additives improved one property on the cost of another ones. Herein, we have synergistically incorporated multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO) with varying loadings as additives in the CF matrix via direct pyrolysis to achieve all the desired properties. Seven different types of CF composites including pure CF were prepared and their effect on the structure, mechanical, thermal, electrical and catalytic characteristics has been reported. The results revealed that after the inclusion of MWCNTs and GO contents, the microstructural performance of CF samples was amazingly improved. Additionally, it was observed that mechanical, thermal, electrical and catalytic behaviors of the CF samples were significantly enhances by the increase of nanohybrids. The compressive strength and Young's modulus reveals their optimum limits up to 19.3 and 57.4 MPa respectively on 2 wt.% MWCNTs-GO additive loadings. Similarly, the greatest thermal and electrical conductivities of 30.92 W/m. K and 27.4 × 103 S/m were showed by CF samples having 2 wt. % MWCNTs-GO loadings. Whereas, the decolorization activity of the CF and their nanocomposites were tested against methyl orange dye and it was observed that the sample with enhanced MWCNTs and GO have good decolorization activity and much sustainable than other samples. The 4% CF/MWCNTs-GO decolorized about 76% MO dye under exposure to UV light within 60 min. The decolorization of MO dye increases with increasing nanocomposite dosage and decreasing initial dye concentration.

A highly efficient low-cost adsorbent was prepared using raw and chemically modified cellulose isolated from sugarcane bagasse for decontamination of Cr(VI) from wastewater. First, cellulose pulp was isolated from sugarcane bagasse by subjecting it to acid hydrolysis, alkaline hydrolysis and bleaching with sodium chlorate (NaClO3). Then, the bleached cellulose pulp was chemically modified with acrylonitrile monomer in the presence Fenton’s reagent (Fe+2/H2O2) to carry out grafting of acrylonitrile onto cellulose by atom transfer radical polymerization. The developed adsorbent (acrylonitrile grafted cellulose) was analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Both raw cellulose and acrylonitrile grafted cellulose were used for chromium removal from wastewater. The effects of metal ion concentration, pH, adsorbent dose and time were studied, and their values were optimized. The optimum conditions for the adsorption of Cr(VI) onto raw and chemically modified cellulose were: metal ion concentration: 50 ppm, adsorbent dose: 1 g, pH: 6, and time: 60 min. The maximum efficiencies of 73% and 94% and adsorption capacities of 125.95 mg/g and 267.93 mg/g were achieved for raw and acrylonitrile grafted cellulose, respectively. High removal efficiency was achieved, owing to high surface area of 79.92 m2/g and functional active binding cites on grafted cellulose. Isotherm and kinetics studies show that the experimental data were fully fitted by the Freundlich isotherm model and pseudo first-order model. The adsorbent (acrylonitrile grafted cellulose) was regenerated using three different types of regenerating reagents and reused thirty times, and there was negligible decrease (19%) in removal efficiency after using it for 30 times. Hence, it is anticipated that acrylonitrile could be utilized as potential candidate material for commercial scale Cr(VI) removal from wastewater.

Nanodiamond (ND) is becoming the core center of interest for many researchers due to its immense utilization in different fields of science. The extraordinarily unique attributes provided by NDs include biocompatibility, easy production, chemical inertness, rich surface chemistry, small size, and fluorescence resistance. In biomedical sciences, all these characteristics uplift the standards of ND particles. Recent studies on the biomedical side have been found to strengthen its significance ever since ND tested positive for utilization in diagnostics and drug delivery. In addition, NDs have been proven beneficial in the manufacturing of biodegradable surgical instruments, scaffolds for tissue engineering, and drugs to eliminate resistant microbes and viruses. Genetic materials are also delivered to the center of the nucleus with the aid of ND particles. In this review, we have discussed in detail all the benefits of NDs, their applications in sensors, ND-blood interactions, blood-contacting, orthopedics, anti-cancer agents, antimicrobial agents, and drug/gene delivery. The importance and significance of the purification, synthesis, processing, and surface functionalization of NDs have been discussed. Recent advances in modern technologies in the field of biomedical and biological sciences also have been covered in this manuscript.

The chemical reduction method was used to synthesize nickel oxide particles (NiO) and NiO supported on titanium dioxide (NiO/TiO2 nanocomposite). The composites were characterized through scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The morphological investigation showed that pseudocubic NiO are present in dispersed as well as agglomerated forms. Whereas NiO particles (

Kaolin clay-supported Zinc oxide (ZnO/KC) and ZnO NPs nanoparticles (NPs) were prepared by a chemical reduction process and used for the photodegradation of methyl red (MR) dye as a photocatalyst. Due to the interlayered porous structure of the KC, we achieved an extremely good association between ZnO NPs and KC. The product confirmation was conducted by Scanning electron microscopy (SEM), X-Ray diffraction (XRD), energy dispersive X-Ray (EDX), and Fourier transforms infrared (FTIR). SEM showed the irregular morphology of ZnO NPs, while ZnO/KC NCs were predominately round-shaped. Moreover, in both cases, NPs were present in both dispersed as well as agglomerated forms with an average particle size below 100 nm. The results acquired from photodegradation analyses show that ZnO NPs and ZnO/KC NCs degraded about 90 and 99% of MR dye respectively, under UV light in a short irradiation time of 10 min. The recovered and re-recovered ZnO NPs and ZnO/KC NCs also considerably photodegraded MR dye in an aqueous medium. The same NPs also exhibit promising bioactivities against two pathogenic bacteria, i.e., Citrobacter and Providencia. The antioxidant activity of ZnO/KC NCs reached to reasonable 70% compared to the 88% activity of the standard ascorbic acid.

There is a global need for lithium-ion battery (LIB) with high specific power density and energy density; however, LIB is very sensitive to temperature. To guarantee the safety and performance of LIB, mini channel liquid-cooled plate was applied as a part of battery thermal management system. In this research, the effect of water mass flow rate and the geometry of liquid-cooled plate channel were investigated. The variation of geometry is affected by the width of the channel on the prismatic battery and the number of channels on the cylindrical battery. The results show that the battery temperature decreases with increasing the inlet mass flow rate, the number and width of cooling channels. Controlling the inlet mass flow rate and cooling channels is not necessary in case certain critical values are avoided. Thus, applying 10â3 kg/sâ1 of mass flow rate in 8 mm channel width effectively decreased the prismatic battery temperature from 45 °C to 30 °C. Moreover, the use of wider channel decreases the pressure drop inside the channel. It can be concluded that by using eight cooling channels with 0.001 kg/sâ1 inlet mass flow rate, the maximum temperature can be controlled up to 12.06 °C for a cylindrical battery. This study helps increasing energy efficiency, which further promotes the circular economy program.

Abstract The Nickel oxide nanoparticles (NiO NPs) and Nickel oxide/Nanoclay nanocomposite (NiO/Nc NC) were synthesized by chemical reduction method and used for the photodegradation of Orange II dyes in aqueous solution. The synthesized samples were characterized through SEM, EDX, FTIR and TGA. The SEM analysis presented that the NiO NPs are spherical with irregular shapes and sizes. The size of particles is in the range of 100–400 nm. It was also observed that the NiO NPs are deposited on the surface of Nanoclay. The EDX study confirmed the formation of metal NPs and verify and purity. The FT-IR spectra of NiO and NiO/Nc NC presented peaks at 432 cm−1 and 504 cm−1, which correspond to NiO while peak at 1090–940 cm−1 is due to Si–O stretching vibration of orthosilicate anions and Si–O–Al groups. The photodegradation study illustrated that the NiO NPs and NiO/Nc NC degraded about 93 and 96% Orange II in aqueous medium, respectively within 20 min. The effect of various parameters like initial concentration of dyes, pH, recycled catalysts, and catalyst dosage were also studied.

Abstract Removal of heavy metals and dyes from wastewater has received great attention due to scarcity of clean water worldwide. Herein an approach was introduced to attain this goal by employing a single material. Chitosan films were prepared, cross-linked it and utilized for the adsorption of cobalt from aqueous medium. The cobalt adsorbed chitosan was then reutilized as a photocatalyst for the photodegradation of methyl violet dyes. The prepared chitosan, cross-linked chitosan and cobalt adsorbed cross-linked chitosan were characterized through scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). SEM and EDX confirmed the adsorption of cobalt on the cross-linked chitosan. TGA analysis proved the increase in thermal stability with cross-linking while FTIR confirmed the cross-linking of chitosan. Maximum cobalt adsorption of 144 mg/g occurs at 600 ppm salt concentration. The photodegradation study shows that the fresh cobalt adsorbed cross-linked chitosan degraded about 97.78% methyl violet dye within 180 min under UV light, while the recovered degraded about 86.97% within the same time. Efficient degradation was observed at low initial dye concentration and at 30 ppm about 92.16% dye degraded.

The conventional chemical methods of nanoparticles synthesis have been effectively replaced by nanoparticle synthesis mediated by plants. The current study describes the environmental friendly synthesis of chromium oxide nanoparticles (Cr2O3 NPs) using Erythrophleum guineense plant extract. The synthesis of Cr2O3 NPs was validated by UV/VIS spectroscopy, Energy Dispersive X-Ray (EDX), Scanning Electron Microscopy (SEM), and X-ray diffraction (XRD) studies. The appearance of the Sharpe peak at 460 nm in the UV/Vis spectrum and the colour change caused by surface plasma resonance confirmed the formation of Cr2O3 NPs. The EDX spectrum of Cr2O3 nanoparticles revealed the presence of carbon, oxygen, and chromium, while SEM analysis revealed an irregular round morphology (with a size below 400 nm). In addition, XRD studies suggested their crystalline nature by the characteristic peaks at 34° and 36° and 42° (2Ɵ), respectively. The green synthesized Cr2O3 NPs showed promise as in-vitro cholinesterase inhibitor at tested concentrations (62.5–1,000 μg/ml), with IC50 values of 120 and 100 μg/ml against Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE), respectively. The results suggested that the green synthesized Cr2O3 NPs could be used in the future to stop enzyme from working and for other biological activities.

Groundwater heavy metal pollution is a major concern all around the world. For the assessment of heavy metals and physico-chemical characteristics, groundwater samples were collected from different locations of the Karak District, Pakistan. With the help of the global information system device (GIS), groundwater samples were collected and studied from 47 locations. The present study focused on the water table (WT), water source depth (WSD), pH, electrical conductivity (EC), dissolved oxygen (DO), total dissolved solids (TDS), lead (Pb(II)), silver (Ag(I)), iron (Fe(II)) and chromium (Cr(VI)) parameters. Heavy metals were analyzed by the Atomic Absorption Spectrophotometer (AAS). The Pearsonâs matrix of correlation showed relationships between several parameters, such as the EC and the TDS which had close interactions between all the three different groundwater samples (collected by hand pump (HP), bore holes (BH) and tube wells (TW)). The strong correlation was detected in all the sources of water between the TDS and the EC, the regression coefficient (r) of which was 1. In the hierarchical clustering (by dendrograms) the HP samples show two clusters: Cluster 1 contains seven parameters and Cluster 2 has four parameters. The BH samples have two clusters: Cluster 1 contains three parameters and Cluster 2 has eight parameters. The TW dendrogram also shows two clusters: Cluster 1 contains six parameters while Cluster 2 has five parameters.

Abstract Nylon 6/6 and ZnO/nylon 6/6 nanocomposite films were prepared by solvent casting method. Morphological study displayed that ZnO NPs are better dispersed in nylon 6/6. However, some agglomerations were found by the incorporation of high quantities of fillers. The thermal stabilities of neat nylon 6/6 films decreased by addition of nanoparticles (NPs). DSC study shows that the NPs slow down the crystallization rate of neat polymer matrix. POM of Nylon 6/6 upon crystallization showed distinct sized spherulites, which decreased by the incorporation of NPs because of nucleation effect of NPs. The mechanical properties of neat polymer are decreased by addition of ZnO NPs, which might be due to agglomeration of fillers. The neat nylon 6/6 and ZnO/nylon 6/6 nanocomposite were used for the photodegradation of alizarin red (AR) dye, which shows that pure nylon 6/6 degraded about 28% dye while 30% ZnO/Nylon 6/6 degraded about 58.3% dye within 5 h irradiation.

Industrial effluents containing dyes are the dominant pollutants, making the drinking water unfit. Among the dyes, methylene orange (MO) dye is mutagenic, carcinogenic and toxic to aquatic organisms. Therefore, its removal from water bodies through effective and economical approach is gaining increased attention in the last decades. Photocatalytic degradation has the ability to convert economically complex dye molecules into non-toxic and smaller species via redox reactions, by using photocatalysts. g-C3N4 is a metal-free n-type semiconductor, typical nonmetallic and non-toxici polymeric photocatalyst. It widely used in photocatalytic materials, due to its easy and simple synthesis, fascinating electronic band structure, high stability and abundant availability. As a photocatalyst, its major drawbacks are its limited efficiency in separating photo-excited electron–hole pairs, high separated charge recombination, low specific surface area, and low absorption coefficient. In this review, we report the recent modification strategies adopted for g-C3N4 for the efficient photodegradation of MO dye. The different modification approaches, such as nanocomposites and heterojunctions, as well as doping and defect introductions, are briefly discussed. The mechanism of the photodegradation of MO dye by g-C3N4 and future perspectives are discussed. This review paper will predict strategies for the fabrication of an efficient g-C3N4-based photocatalyst for the photodegradation of MO dye.

Hepatitis C virus (HCV) infections are public health problem across the globe, particularly in developing countries. Pakistan has the second highest prevalence of HCV infection worldwide. Limited data exist from Pakistan about persons who inject drugs (PWID) and are at significant risk of exposure to HCV infection and transmission. Serum specimens (n = 110) collected from PWID residing in four provinces were tested for molecular markers of HCV infection. Next generation sequencing (NGS) of the hypervariable region (HVR1) of HCV and Global Hepatitis Outbreak and Surveillance Technology (GHOST) were used to determine HCV genotype, genetic heterogeneity, and construct transmission networks. Among tested specimens, 47.3% were found anti-HCV positive and 34.6% were HCV RNA-positive and belonged to four genotypes, with 3a most prevalent followed by 1a, 1b and 4a. Variants sampled from five cases formed phylogenetic cluster and a transmission network. One case harbored infection with two different genotypes. High prevalence of infections and presence of various genotypes indicate frequent introduction and transmission of HCV among PWID in Pakistan. Identification of a transmission cluster across three provinces, involving 20% of all cases, suggests the existence of a countrywide transmission network among PWIDs. Understanding the structure of this network should assist in devising effective public health strategies to eliminate HCV infection in Pakistan.

Photodegradation is the chemical conversion of large, toxic, and complex molecules into non-toxic, simpler, and lower molecular weight species due to light exposure. Heterogeneous photocatalysis has sufficient potential to degrade toxic organic pollutants present in wastewater. As industries discharge their effluents containing organic pollutants into natural water bodies, which penetrate into the subsurface through connected pores it is necessary to study this process in natural or tap water. Tap water (TW) is mainly obtained from underground wells having inorganic salts in a minute quantity with a conductivity of 500 μS/cm. TW contains inorganic anions, which affect the photocatalytic activity and photocatalysis process. The aim of this review is to evaluate the effect of TW on the photo-degradation of organic pollutants such as dyes, pharmaceutical products, pesticides, etc., with the support of the literature. The TW had a diverse effect on the photodegradation of organic pollutants; either it may enhance or decrease the rate of pollutants’ photodegradation.

Abstract Functionalized multiwalled carbon nanotubes (F-MWCNTs)/Co–Ti oxide nanocomposites and neat Co–Ti oxide nanoparticles were synthesized by chemical reduction method. The scanning electron microscopy micrographs show that the bimetallic NPs in F-MWCNTs/Co–Ti are present in dispersed form while the neat Co–Ti nanoparticles were found in agglomerated form. The formation of nanocomposites and neat Co–Ti nanoparticles was also confirmed by energy-dispersive X-ray. Both types of nanocomposites were employed as photocatalyst for the photodegradation of Rhodamine B in aqueous medium under UV light irradiation. The photodegradation study was performed via UV–Vis spectrophotometer. The photodegradation results show that F-MWCNTs/Co–Ti oxide NPs degraded about 93.35% dye within 150 min irradiation time while the neat Co–Ti oxide NPs degraded about 91.76% dye within same irradiation time. The F-MWCNTs/Co–Ti can be easily removed and recycled due to its bulky composite nature as compared to neat Co–Ti oxide NPs. The effect of dye concentration, catalyst dosage, pH of medium and activity of recycled catalyst was also evaluated.

The synergistic effect of binary CdTiO2 and ternary NiCdTiO2 on the photocatalytic efficiency of TiO2 nanoparticles was investigated. The SEM analysis demonstrates spherical TiO2 NPs of different sizes present in agglomerated form. The structural analysis of the nanocomposites reveals a porous structure for TiO2 with well deposited Cd and Ni NPs. TEM images show NiCdTiO2 nanocomposites as highly crystalline particles having spherical and cubical geometry with an average particle size of 20 nm. The EDX and XRD analysis confirm the purity and anatase phase of TiO2, respectively. Physical features of NiCdTiO2 nanocomposite were determined via BET analysis which shows that the surface area, pore size and pore volume are 61.2 m2/g, 10.6 nm and 0.1 cm3/g, respectively. The absorbance wavelengths of the CdTiO2 and NiCdTiO2 nanocomposites have shown red shift as compared to the neat TiO2 due to coupling with Ni and Cd that results in the enhanced photocatalytic activity. The photocatalytic activity demonstrated that TiO2, CdTiO2 and NiCdTiO2 degrade methylene blue (MB) and methyl green (MG) about 76.59, 82, 86% and 63.5, 88, 97.5%, respectively, at optimum reaction conditions.

Waste management and energy generation are the foremost concerns due to their direct relationship with biological species and the environment. Herein, we report the utilization of iron rust (inorganic pollutant) as a photocatalyst for the photodegradation of methylene blue (MB) dye (organic pollutant) under visible light (economic) and water oxidation (energy generation). Iron rust was collected from metallic pipes and calcined in the furnace at 700 °C for 3 h to remove the moisture/volatile content. The uncalcined and calcined rust NPs are characterized through scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier-transform infrared (FTIR) analysis, X-ray Diffraction (XRD), and thermogravimetric analysis (TGA). The morphological study illustrated that the shape of uncalcined and calcined iron rust is spongy, porous, and agglomerated. The XRD and DLS particle sizes are in a few hundred nanometers range. The photodegradation (PD) investigation shows that calcined rust NPs are potent for the PD of modeled MB, and the degradation efficiency was about 94% in a very short time of 11 min. The photoelectrochemical (PEC) measurements revealed that calcined rust NPs are more active than uncalcined rust under simulated 1 SUN illumination with the respective photocurrent densities of ~0.40 and ~0.32 mA/cm2. The density functional theory simulations show the chemisorption of dye molecules over the catalyst surface, which evinces the high catalytic activity of the catalyst. These results demonstrate that cheaper and abundantly available rust can be useful for environmental and energy applications.

This review is provided a detailed overview of the synthesis, properties and applications of nanoparticles (NPs) exist in different forms. NPs are tiny materials having size ranges from 1 to 100 nm. They can be classified into different classes based on their properties, shapes or sizes. The different groups include fullerenes, metal NPs, ceramic NPs, and polymeric NPs. NPs possess unique physical and chemical properties due to their high surface area and nanoscale size. Their optical properties are reported to be dependent on the size, which imparts different colors due to absorption in the visible region. Their reactivity, toughness and other properties are also dependent on their unique size, shape and structure. Due to these characteristics, they are suitable candidates for various commercial and domestic applications, which include catalysis, imaging, medical applications, energy-based research, and environmental applications. Heavy metal NPs of lead, mercury and tin are reported to be so rigid and stable that their degradation is not easily achievable, which can lead to many environmental toxicities. Keywords: Nanoparticles, Fullerenes, Optical, Plasmonic, Toxicity

We investigated the shear banding phenomena in the non-isothermal simple-shear flow of a viscoelastic-fluid-based nanofluid (VFBN) subject to exothermic reactions. The polymeric (viscoelastic) behavior of the VFBN was modeled via the Giesekus constitutive equation, with appropriate adjustments to incorporate both the non-isothermal and nanoparticle effects. Nahme-type laws were employed to describe the temperature dependence of the VFBN viscosities and relaxation times. The Arrhenius theory was used for the modeling and incorporation of exothermic reactions. The VFBN was modeled as a single-phase homogeneous-mixture and, hence, the effects of the nanoparticles were based on the volume fraction parameter. Efficient numerical schemes based on semi-implicit finite-difference-methods were employed in MATLAB for the computational solution of the governing systems of partial differential equations. The fundamental fluid-dynamical and thermodynamical phenomena, such as shear banding, thermal runaway, and heat transfer rate (HTR) enhancement, were explored under relevant conditions. Important novel results of industrial significance were observed and demonstrated. Firstly, under shear banding conditions of the Giesekus-type VFBN model, we observed remarkable HTR and Therm-C enhancement in the VFBN as compared to, say, NFBN. Specifically, the results demonstrate that the VFBN are less susceptible to thermal runaway than are NFBN. Additionally, the results illustrate that the reduced susceptibility of the Giesekus-type VFBN to the thermal runaway phenomena is further enhanced under shear banding conditions, in particular when the nanofluid becomes increasingly polymeric. Increased polymer viscosity is used as the most direct proxy for measuring the increase in the polymeric nature of the fluid.

The unavailability of clean drinking water is one of the significant health issues in modern times. Industrial dyes are one of the dominant chemicals that make water unfit for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to human health and environmental safety. It is usually released in natural water sources, which becomes a health threat to human beings and living organisms. Hence, there is a need to develop an environmentally friendly, efficient technology for removing MB from wastewater. Photodegradation is an advanced oxidation process widely used for MB removal. It has the advantages of complete mineralization of dye into simple and nontoxic species with the potential to decrease the processing cost. This review provides a tutorial basis for the readers working in the dye degradation research area. We not only covered the basic principles of the process but also provided a wide range of previously published work on advanced photocatalytic systems (single-component and multi-component photocatalysts). Our study has focused on critical parameters that can affect the photodegradation rate of MB, such as photocatalyst type and loading, irradiation reaction time, pH of reaction media, initial concentration of dye, radical scavengers and oxidising agents. The photodegradation mechanism, reaction pathways, intermediate products, and final products of MB are also summarized. An overview of the future perspectives to utilize MB at an industrial scale is also provided. This paper identifies strategies for the development of effective MB photodegradation systems.

Abstract Zirconia-supported palladium (Pd/ZrO2) and Zirconia-supported platinum (Pt/ZrO2) nanoparticles (NPs) are synthesized from their precursors via impregnation technique. The Pd/ZrO2 and Pt/ZrO2 NPs were analyzed via SEM and EDX, while the study of indigo disulfonate dye degradation was carried out by UV/VIS spectrophotometer. The SEM micrographs illustrated that the Pd and Pt NPs were well placed on ZrO2 surface. The Pd/ZrO2 and Pt/ZrO2 NPs were also employed as photocatalysts for the photodegradation of indigo disulfonate in an aqueous medium under UV-light irradiation. The photodegradation study presented that Pd/ZrO2 and Pt/ZrO2 NPs degraded 96 and 94% of indigo disulfonate in 14 h, respectively. The effect of pH of medium and catalyst dosage and efficiency of recovered Pd/ZrO2 and Pt/ZrO2 NPs on the photocatalytic degradation were also studied. It was also found that the maximum degradation of dye was found at pH 10 (95–97%) and at 0.02 g weight (40.28%).

The adsorptive removal of lead (II) from aqueous medium was carried out by chemically modified silica monolith particles. Porous silica monolith particles were prepared by the sol-gel method and their surface modification was carried out using trimethoxy silyl propyl urea (TSPU) to prepare inorganic–organic hybrid adsorbent. The resultant adsorbent was evaluated for the removal of lead (Pb) from aqueous medium. The effect of pH, adsorbent dose, metal ion concentration and adsorption time was determined. It was found that the optimum conditions for adsorption of lead (Pb) were pH 5, adsorbent dose of 0.4 g/L, Pb(II) ions concentration of 500 mg/L and adsorption time of 1 h. The adsorbent chemically modified SM was characterized by scanning electron microscopy (SEM), BET/BJH and thermo gravimetric analysis (TGA). The percent adsorption of Pb(II) onto chemically modified silica monolith particles was 98%. An isotherm study showed that the adsorption data of Pb(II) onto chemically modified SM was fully fitted with the Freundlich and Langmuir isotherm models. It was found from kinetic study that the adsorption of Pb(II) followed a pseudo second-order model. Moreover, thermodynamic study suggests that the adsorption of Pb(II) is spontaneous and exothermic. The adsorption capacity of chemically modified SM for Pb(II) ions was 792 mg/g which is quite high as compared to the traditional adsorbents. The adsorbent chemically modified SM was regenerated, used again three times for the adsorption of Pb(II) ions and it was found that the adsorption capacity of the regenerated adsorbent was only dropped by 7%. Due to high adsorption capacity chemically modified silica monolith particles could be used as an effective adsorbent for the removal of heavy metals from wastewater.

A specific finger-projected fixed-bed reactor (FPFBR) was designed to efficiently utilize magnetic nanoparticles (MnFe2O4/Bi-MnFe2O4) for a model reaction (hydrogenation of a greenhouse gas, CO2, to valuable products: VPs). Coprecipitation method, with desired modification was used for the preparation of magnetic nanoparticles (MNPs) with controlled shape and size. Eighteen fingers in a single chamber were designed in the fixed-bed reactor’s skeleton; each finger worked as an independent reaction core. Controlled flow of hydrogen and CO2 was continuously provided to preheated reaction cores (catalyst beds) from saturator. One of the major products methanol {(%: Conv, 22/Sel 61)} among VPs was identified and quantified by GC. The efficiency of self-designed reactor was 74% for the direct catalytic hydrogenation of CO2 to valuable organic products.

This research inspects the liquid film flow of the nanofluid in a permeable medium with the consequence of thermal radiation over a stretching sheet. The viscidness and thermal conduction of the nanofluid varies with temperature in such a manner that the thermal conductivity considered in direct relation while the viscosity considered inversely proportional to the temperature field. The invariable magnetic field applies vertically to the flow field in the existence of entropy generation. For the above-mentioned nanofluid study, Buongiorno’s model is used. The leading equations are changed into a set of third- and second-order nonlinear coupled differential equations. These nonlinear ordinary differential equations are solved using the optimal approach of homotopy analysis method. The physical appearance of the modelled parameters based on the liquid film thickness is mainly focused. Furthermore, the influence of embedded parameters like variable viscosity parameter Λ , Prandtl number Pr , Schmidt number Sc , Brinkman number Br , Brownian motion constraint Nb , thermophoresis constraint Nt , magnetic parameter M , thermal radiation parameter Nr , Reynolds number Re , diffusion coefficient λ , non-dimension temperature variation χ and non-dimension concentration variation Ω is observed on the velocity pitch, temperature gradient and concentration sketch. The consequence of parameters due to entropy generation and Bejan number has also been observed in this work. The important physically quantities of skin friction coefficient, the local Nusselt number and Sherwood number have also been studied. Residual error and optimal values have been calculated for the range of each physical parameter. The present work is compared with the published work and the comparison has been shown physically and numerically.