This work involves the strategic design and fabrication of novel hybrid beads, consisting of an organic and an inorganic layer for co-adsorption of Congo Red (CR) and Crystal Violet (CV) dyes from a binary mixture. A series of hybrid biopolymer-based adsorbents having variable compositions was synthesised by crosslinking Chitosan (CS) with Glutaraldehyde (GL) and embedding Kaolin (kao), followed by surface grafting with 2-Hydroxyethyl Methacrylate (HEMA) monomers. Among the multiple adsorbents tested, one of the optimised hybrid formulations (AC-20) with 79.3% crystallinity was found to effectively co-adsorb 99.7% of CR and 95.4% of CV simultaneously from a binary mixture of 10 ppm strength at pH 1 in 4 hours at a temperature of 313 K using an adsorbent dosage of 0.05 g/10 mL. Effective dye removal was retained even at pH=3 leading to 84.9% CR and 91.9% CV removal from binary dye mixture. Several characterisation techniques, including FTIR analysis, swelling studies, zeta potential analysis, UV-visible spectroscopy, SEM-EDX and XRD analysis, were performed. Kinetic modelling described that CR (R 2 =0.997) and CV (R 2 =0.996) adsorption followed the pseudo-second-order model. This study successfully addresses both environmental hazards and practical wastewater treatment needs by using the eco-friendly adsorbent beads as a promising solution for real-world remediation of toxic dye mixtures.

The development of multifunctional nanostructured adsorbents is vital for addressing water pollution caused by heavy metals and halogen species. Herein, polypyrrole nanotubes (PPy NTs) were synthesized via a soft-template approach using methyl orange (MO) as the structure-directing agent and FeCl3 as the oxidant. The resulting PPy NTs exhibited tubular morphology, high surface area, and abundant electron-rich sites, enabling efficient uptake of silver ions (Ag+) from aqueous solution. Owing to the intrinsic redox activity and presence of Cl dopant ions of PPy, the adsorbed Ag+ ions were subsequently reduced in-situ to metallic Ag NPs and AgCl (Ag-AgCl NPs), yielding well-dispersed Ag-AgCl nanoparticles decorated PPy NTs nanocomposite (Ag-AgCl@PPy NTs) without the need for additional reducing or stabilizing agents. The formation of Ag-AgCl@PPy NTs was validated by FTIR, XRD, BET, FE-SEM, HR-TEM-STEM, and XPS, confirming the well dispersion of Ag-AgCl NPs across the PPy surface. The hybrid nanocomposites displayed synergistic adsorption that was further exploited for the adsorption of iodine from water. Adsorption experiments in batch mode demonstrated that Ag-AgCl@PPy NTs achieved significantly higher iodine removal efficiency (90.6%) compared to pristine PPy NTs (68.2%), highlighting the role of Ag-AgCl NPs in enhancing halogen sequestration. The Langmuir maximum adsorption capacity for iodine removal was found to be 1482 mg/g at 25 degrees C. Moreover, the nanocomposites exhibited fast removal kinetics and good reusability, underscoring their stability. This dual-functional strategy not only eliminates toxic Ag+ ions but also transforms them into value-added hybrid nanomaterials with superior pollutant removal capacity.

Copper nanoparticles (Cu NPs) supported on sulfonic acid-doped polyaniline nanotube nanocomposites (Cu@PANI/NSA NCs) served as a high-performing catalyst for various organic transformation reactions. The NCs were prepared through one-pot polymerization of phenylamine monomers in the occurrence of ammonium persulfate (APS) and 2-naphthalenesulfonic acid (2-NSA), followed by Cu NPs deposition using hydrazine reduction. The prepared NCs were investigated through high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), Xray diffraction (XRD), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Among the three catalytic formulations, Cu@PANI/NSA-1 (12% Cu NPs loading) exhibited the highest activity for reducing 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Kinetic studies revealed an activation energy of 47.87 kJ mol-1, achieving a pseudo-first-order rate coefficient of 0.18667 min- 1 (25 degrees C), 0.2911 min-1 (35 degrees C), 0.6379 min- 1 (45 degrees C), and 0.9804 min- 1 (55 degrees C), consistent with the Langmuir-Hinshelwood model. Cu@PANI/NSA-1 retained excellent stability, showing negligible drop-in activity following eight consecutive cycles. Additionally, the nanocomposite efficiently catalyzed ligand-free C-O and C-N coupling reactions.

Electromagnetic (EM) shielding plays a crucial role in modern technology, protecting sensitive electronic devices from interference and ensuring efficient operation. This review explores the basic ideas of polymer nanocomposite-based EM shielding, emphasizing the mechanisms and theories that underlie its effectiveness. Understanding shielding processes of polymer-based EMI shields is crucial, given the growing demand for electronic devices and the pervasiveness of EM interference (EMI). The literature on EM shielding mechanisms is summarized in this review, which also clarifies important theories, including absorption, reflection, and multiple internal reflections in materials. It also looks at how polymeric nanocomposites' special structural and material characteristics can improve shielding efficacy. By analyzing the theoretical frameworks and experimental findings, this review unveils the intricate interplay between material properties and EM shielding performance. It discusses the influence of factors like filler type, concentration, morphology, and interface on shielding effectiveness (SE), providing insights into optimizing polymer nanocomposite designs for superior EMI mitigation. Thus, this review consolidates the theoretical foundations and practical insights into EM shielding mechanisms. It underscores the significance of polymer-based nanocomposites as promising candidates for next-generation EMI shielding materials, offering a pathway towards developing smart polymers with tailored properties for diverse applications in electronics and telecommunications.

The materialization of polybutylene succinate (PBS) belongs to the family of polyesters which are degradable and biodegradable, their biodegradability properties have attracted enormous interest for product development towards different polymer-based applications. Besides its biodegradability, PBS can be derived from petroleum and biobased monomers. At the same time, the latter is the driving factor for its growing interest in bioplastics for fully green and sustainable biobased-derived polymer products. The processes and techniques presented herein, are based on the production of biobased succinic acid monomer to PBS. However, the counterpart biobased monomer 1,4-butanediol (1,4-BDO) production has not been commercially demonstrated. This review discusses the progress in state-of-the-art developments in the synthesis strategies of PBS, its copolymers, and composites with the view to improve molecular weight, thermal, and mechanical properties. It further analyzes the different strategies to synthesize modified PBS polymer composites from organic and inorganic nanofillers to enhance their chemical, thermal, stability and mechanical structural properties. Importantly, the review highlights the progress in the applications of PBS copolymers and composites with tailored structure-designed properties for specific sectors such as packaging films, biomedical and drug release, fire retardants, and agricultural products. The structure-functional performance characteristics of these developments in the PBS, copolymers, and composites are highlighted to provide baseline insights for future developments in engineering the specific applications, and structural interface PBS composites with enhanced structure-functional performance properties.

A facile technique is utilized to fabricate silver decorated polyaniline nanowires (PANI/Ag NWs) via simultaneous formation of the camphor sulphonic acid doped PANI and Ag NPs. Herein, Ag NPs were formed through the in-situ reduction of Ag+ ions by electron rich polymer matrix without using external reducing agent. Comprehensive characterization confirmed the successful deposition of Ag NPs onto the nanowire-like PANI matrix. The prepared NWs were successfully applied as efficient catalysts and demonstrated enhanced catalytic activity, achieving nearly complete degradation (99.9 %) of Congo red (CR) within 60 minutes using 0.2 g/L of catalyst and 5 mM NaBH4 at 25 degrees C. The degradation efficiency increased with higher NWs and NaBH4 dosages but declined with increasing pH and CR concentration. Although the pseudo-first-order kinetic model provided a reasonable fit under strongly reactive conditions, it performed poorly in the absence of NaBH4 and under non-ideal conditions due to its empirical limitations whereas the Langmuir-Hinshelwood model predicts that the degradation proceeds via competitive surface adsorption followed by catalytic cleavage of CR at the catalyst interface. Importantly, the Langmuir-Hinshelwood model enabled consistent fitting across varied operational parameters using a single set of kinetic parameters, highlighting its scalability and predictive strength for industrial applications. Recyclability tests over eleven cycles showed that the NWs retained nearly full catalytic performance up to the 10th reuse, indicating excellent stability. Liquid chromatography-mass spectrometry analysis revealed that degradation of CR proceeded via reductive cleavage of azo bonds, resulting in the formation of various colourless degradation products.

This study presents a straightforward methodology for synthesizing polyaniline/cobalt hydroxide nanocomposites (PANI@Co(OH)2 NCs). The NCs were prepared by reductively supporting Co(OH)2 nanoparticles (NPs) onto pre-synthesized polyaniline nanotubes (PANI NTs) matrix. These NCs were then utilized as catalysts for the reductive degradation of Congo red (CR) dye in the presence of sodium borohydride (NaBH4) as a reducing agent. Characterization results confirmed the effective formation of nanosized Co(OH)2 NPs on the surface of the nanotubular PANI. The PANI@Co(OH)2 NCs demonstrated exceptional catalytic performance, achieving 99.9 % degradation of 100 mg/L CR dye within 30 min using a minimum dosage of 0.2 g/L PANI@Co (OH)2 NCs and 0.5 mM NaBH4. The degradation efficiency improved with increasing dosages of both the catalyst and NaBH4 but decreased with higher initial CR concentrations and elevated solution pH. The degradation kinetics followed a pseudo-first-order model. Recycling experiments revealed that the PANI@Co(OH)2 NCs maintained 99.9 % CR degradation efficiency through five consecutive cycles, indicating excellent reusability of the catalyst. Liquid chromatography-mass spectrometry (LC-MS) analysis of the degradation products suggested that the degradation mechanism involves reductive cleavage of azo bonds, leading to the formation of naphthalene sulfonate ions and other aromatic intermediates. This work highlights the potential of PANI@Co(OH)2 NCs as a highly efficient and recyclable catalyst for the treatment of azo dye pollutants.

Tobacco-specific N-nitrosamines (TSNAs), which are associated with several cancers, are formed during the processing of tobacco alkaloids. Since tobacco smoking poses serious health risks, scientists, governments, and health regulators globally have denounced it and categorized its constituents according to their carcinogenicity. Tobacco smoke investigations are guided by standardized methods (ISO). With the help of standardized smoke-generating machines, precise quantification of TSNAs and other smoke constituents is now possible thanks to advancements in analytical techniques. This information supports initiatives to reduce the amount of TSNAs that smoking exposes people to. This review covers the occurrence, formation pathways, precursors, and control strategies through removal technologies, providing thorough analysis of the state of science today regarding TSNAs. The adsorption characteristics of different materials as possible filter additives or modifiers are critically discussed, emphasizing important elements like porosity, layering, acidity/alkalinity, and surface area that affect their performance for capturing TSNAs from smoke. While scientific understanding of these areas is still evolving, this review intends to provide for the first time research progress on the adsorption properties of various materials, including zeolites, silica, few-layer black phosphorus, metal-organic frameworks, and molecularly imprinted polymers, among others, for reducing TSNAs present in both cigarette smoke and aqueous solutions.

Hybrid nanocomposite (NC) materials comprising organic polymers and inorganic metal nanoparticles (NPs) with unique properties are popular for their advanced technological applications including resistive switching memory devices. Herein, NCs of 2-naphthalene sulphonic acid-doped polyaniline nanotubes (PANI-NSA NTs) and nickel nanoparticles (Ni NPs) were synthesized via a facile chemical synthesis procedure where metallic Ni NPs were embedded in/deposited onto the surface of PANI-NSA NTs by a simple reduction method. Different characterization methods revealed successful deposition of weak ferromagnetic Ni NPs onto the PANI-NSA matrix. The bipolar resistive switching behaviour of the as-synthesized PANI-NSA + Ni NCs was investigated under the application of voltage stress in a two-terminal sandwiched device configuration. The fabricated indium tin oxide/PANI-NSA + Ni/silver (ITO/PANI-NSA + Ni/Ag) device displays bipolar resistive switching properties having a memory window of ∼1.5 × 10 3 , and switches effectively over 200 cycles. Ohmic conduction in the lower-voltage regime and the space-charge-limited Mott–Gurney current conduction model in the higher-voltage region were identified as major charge conduction mechanisms in the high resistive state of the device. On the other hand, in the entire low resistive state region the experimental data followed the Mott–Gurney conduction model.

Nanosized cobalt (Co) particles exhibit unique chemical, magnetic, electronic, and catalytic properties. Like nanoscale metallic iron, nanostructured Co and its composite nanostructures also show significant potential for the removal of toxic metal cations from water and wastewater. To explore this potential, composite nanorods (CNRs) of nanosized Co immobilized polyaniline (PANI) nanorods (NRs) matrix (PANI-Co CNRs) were synthesized and effectively applied for the treatment of lead ions (Pb2⁺), serving as a model for heavy metal pollutants in water bodies. Physico-chemical characterization of PANI-Co CNRs revealed that weak ferromagnetic Co nanoparticles (NPs) were effectively deposited onto the surface of the PANI NRs. The enhanced surface properties and superior reactivity of PANI-Co CNRs resulted in greater Pb2+ removal efficiency compared to their individual components. The adsorption kinetics were notably rapid, with the time required to reach equilibrium varying between 60 and 150 min for initial concentrations ranging from 50 to 150 mg/L, all at a pH of 5.0. The isotherm data revealed an impressive Pb2+ adsorption capacity of 1130 mg/g at 25 °C, as determined using the non-linear Langmuir model. Exothermic and spontaneous Pb2+ removal process was deduced from the thermodynamic investigations. Among co-contaminating metal ions, only Cu2+ ions significantly affected the Pb2+ removal performance of the PANI-Co CNRs, implying its possible applications in decontaminating industrial effluent laden with various metal ions. Mechanistic investigation revealed that the treatment process primarily involves the adsorption and precipitation of Pb2+ onto the surface of PANI-Co CNRs, followed by its subsequent reduction to form metallic Pb (Pb0).

This research focuses on valorising waste burnt tires (BTs) through a two-phase oxidation process, leading to the production of onion-like carbon-based nanostructures. The initial carbonization of BTs yielded activated carbon (AC), denoted as “BTSA”, followed by further oxidation using the modified Hummer’s method to produce onion-like carbon designated as “BTHM”. Brunauer–Emmett–Teller (BET) surface area measurements showed 5.49 m2/g, 19.88 m2/g, and 71.08 m2/g for raw BT, BTSA, and BTHM, respectively. Additional surface functionalization oxidations were observed through Fourier-Transform Infrared (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) analyses. Raman spectroscopy indicated an increased graphitic nature during each oxidation stage. BTHM was assessed in batch adsorption studies for cupric wastewater remediation, revealing a two-phase pseudo-first-order behaviour dominated by mass transfer to BTHM. The maximum adsorption capacity for Cu2+ on BTHM was determined as 136.1 mg/g at 25 °C. Langmuir adsorption isotherm best described BTHM at a solution pH of 6, while kinetics studies suggested pseudo-second-order kinetics. Furthermore, BTHM, laden with Cu2+, served as a catalyst in a model coupling reaction of para-idoanisole and phenol, successfully yielding the desired product. This study highlights the promising potential of BTHM for both environmental remediation and catalytic reuse applications to avoid the generation of secondary environmental waste by the spent adsorbent.

AbstractThis study explored the fabrication of Polypyrrole (PPy) and Granular Activated Carbon (GAC) composites (PPy‐GAC) for effective removal of toxic hexavalent chromium (Cr(VI)) from aqueous solutions. Two synthesis methods are employed: (1) electrostatic deposition of PPy onto pre‐charged GAC paper and (2) in‐situ chemical polymerization of pyrrole monomer with GAC particles. Batch adsorption experiments investigated the impact of various operational parameters on Cr(VI) removal. Compared to pristine GAC (54.64 mg g−1), the PPy‐GAC composite exhibited a remarkable 3‐fold increase in equilibrium adsorption capacity, reaching 175.44 mg g−1. Pseudo‐second‐order kinetic model (R2 > 0.999) accurately described the adsorption kinetics, while the Langmuir isotherm model (R2 > 0.99) provided a good fit for the equilibrium data. Maximum adsorption capacity (qmax) increased with temperature, reaching 204.08, 243.90, and 270.27 mg g−1 at 298, 308, and 318 K, respectively. Furthermore, a fixed‐bed column experiment examined the composite's effectiveness in continuous Cr(VI) removal, demonstrating its suitability for practical applications. Notably, the PPy‐GAC composite successfully removed Cr(VI) from a real wastewater sample containing 68 µg L−1 Cr(VI) obtained from a ferrochrome industry, highlighting its potential for real‐world remediation.

Addressing the need for accessible SARS-CoV-2 testing, carboxy-PEG 12-thiol functionalized gold nanoparticles conjugates were developed for rapid point-of-care (POC) detection against SARS-CoV-2 spike protein, pseudo-SARS-CoV-2, and authentic Beta SARS-CoV-2 virus particles. These conjugates leverage gold nanoparticles (AuNPs) as signal transducers, cross-linked to either angiotensin-converting enzyme 2 (ACE2) or SARS-CoV-2 spike protein receptor-binding domain (RBD) antibodies as bioreceptors and showed a distinct color shift from pink to blue. To assess their POC feasibility, the conjugates were integrated into facemasks and breathalyzers, wherein aerosolized SARS-CoV-2 antigens were successfully detected, producing a color change within 10 and 30minutes for the breathalyzer and facemask prototypes, respectively. Furthermore, we explored quantitative analysis using varying concentrations of SARS-CoV-2 spike protein. Both conjugates demonstrated a linear relationship between blue color intensity and virus concentration, with linear ranges of 0.08-0.6ng/mL and 0.04-0.5ng/mL, respectively. Low limits of detection and quantification were also achieved. They exhibited specificity, responding solely to SARS-CoV-2 even in complex matrices containing diverse proteins, including the SARS-CoV-1 spike protein. Precision tests yielded coefficient of variations below 2%, showcasing their remarkable reproducibility. This work presents a promising approach for rapid, sensitive, and specific POC detection of SARS-CoV-2 paving the way for improved pandemic response and management.

Water pollution emanated from the use of mercury ions remains one of the most precarious environmental issue that is currently receiving prominent interest from governments and scientists all over the world due to its detrimental effects on ecosystem. Consequently, significant progress is being achieved towards the adsorptive removal of mercury from polluted waters especially through the material sciences, as evidenced by the large number of published books and journal articles. In this review, authors endeavoured to comprehensively provide insights into the recently developed carbon-based adsorbents (CBAs) for the sequestration of aqueous mercury [Hg (II)]. The synthesis procedures of some latest developed CBAs adsorbents, and their respective performances in Hg (II) removal from water are the main focus in this paper. Further, performance comparison and responsible adsorption mechanisms for Hg (II) adsorption corresponding to specific adsorption media is elaborated. Therefore, the importance, achievements and limitations of various routes with references to their major applications especially in the mercury removal from water are critically reviewed in this study. The outcomes of this review is worthwhile towards synthesis of efficient and practical CBAs and in the design of adsorption systems for wastewater remediation.

Metallic nanoparticles supported on porous matrices are promising heterogeneous catalysts for Fenton-like reaction towards the degradation of organic contaminants in water. Herein, novel magnetic nanocomposites (NCs) of metallic nickel (Ni-0) nanoparticles and nanotubular polyaniline matrix (PANI/Ni-0 NCs) were fabricated by simple reductive formation of Ni-0 nanoparticles upon the pre-synthesized PANI nanotubes (NTs) surface and applied as heterogeneous Fenton-like catalyst in degrading cationic brilliant green dye (BG) in aqueous solution. Various physico-chemical characterization techniques revealed effective supporting of soft ferromagnetic well dispersed nano-dimensional Ni-0 particles onto the PANI NTs matrix. Heterogeneous Fenton-like catalytic performance of PANI/Ni-0 NCs for BG degradation in the presence of hydrogen peroxide (H2O2) oxidant demonstrated their superiority when compared with unsupported Ni0 nanoparticles counterpart. Experiments with a minimum 0.1 g/L of NCs and 10 mM of H2O2 displayed complete degradation of 100 mg/L BG within 120 min reaction time. Improved BG degradation was observed with increase in the dose of PANI/Ni-0, H2O2 concentration and temperature, whereas it reduced with rise in initial concentration of BG. The rate of degradation was well described by the pseudo -first-order kinetic model. Six consecutive BG degradation experiments confirmed NCs reusability without loss of original (similar to 100%) degradation efficiency up to the fifth cycle. Finally, liquid chromatography-mass spectrometric (LC-MS) analyses of the BG samples after 120 min degradation time exposed the formation of N,N-diethylaniline as degradation product along with partial mineralization of the other end products via the attack of reactive hydroxyl radicals (HO center dot) produced in the catalytic system. (C) 2021 Elsevier Inc. All rights reserved.

This study focuses on a greener approach to synthesizing activated carbon by carbonizing Platamus occidentalis tree fibers (TFSA) with 98% H2SO4 at 100 °C. The resulted TFSA was employed as an effective adsorbent for copper ions in aqueous media, yielding copper decorated TFSA (Cu@TFSA). The successful adsorption of copper onto the TFSA was proven through extensive characterization techniques. Herein, the TEM and XPS showed that copper nanoparticles were formed in situ on the TFSA surface, without the use of additional reducing and stabilizing agents nor thermal treatment. The surface areas of TFSA and Cu@TFSA were 0.0150 m2/g and 0.3109 m2/g, respectively. Applying the Cu@TFSA as an antimicrobial agent against Escherica coli ( E. coli) and Salmonella resulted in the potential mitigation of complex secondary pollutants from water and wastewater. The Cu@TFSA exhibited outstanding antimicrobial activity against E. coli and Salmonella in both synthetic and raw water samples. This demonstrated a complete growth inhibition observed within 120 min of exposure. The bacteria inactivation took place through the destruction of the bacteria cell wall and was confirmed by the AFM analysis technique. Cu@TFSA has the potential to be used in the water and wastewater treatment sector as antimicrobial agents.

A PANI-coated heterojunction of WO3@TiO2 nanocomposite was fabricated in three stages. The performance evaluation of the prepared photocatalyst for the degradation of ibuprofen was performed under visible light. Characterization of the photocatalyst using X-ray diffraction (XRD) analysis showed that the TiO2 prepared constituted of the anatase phase. Furthermore, results from in situ XRD analysis of WO3 show that it consisted of monoclinic and orthorhombic crystalline structures. These phases were not affected by the incorporation of PANI as revealed by XRD analysis. Results from Transmission electron microscopy (TEM) examination showed that sphere-like WO3 and TiO2 nanorods of different sizes were prepared In addition, fabrication of a heterojunction of WO3@TiO2 wrapped in PANI was shown by TEM analysis. Results from photoluminescence studies indicate that coupling TiO2 with WO3 enhanced the charge separation and the degradation performance of the nanocomposite. Supporting the heterojunction on PANI enhanced the degradation efficiency as indicated during the performance evaluation process. Diffuse reflectance spectra (DRS) calculations of the PANI/WO3@TiO2 catalysts showed that they can be used under visible light. The experimental results of X-ray Photon Spectroscopy (XPS) analysis showed the presence of elements W, C, O, Ti, and N. Solution pH influenced the degradation process and the maximum degradation efficiency was attained at pH 9. The degradation followed the Langmuir-Hinshelwood kinetic model with a Kinetic constant of 3.5 × 10−2. The rate of degradation increased in the presence of bicarbonate/carbonate ions and persulfate ions.

This paper employed the heat treatment method to obtain g-C3N4/In2O3 composite semiconductor following the deposition-precipitation technique. The physical characterization of the composite semiconductor included diffused reflectance spectroscopy (DRS), X-Ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL). There have been significant and promising outputs regarding photoelectrochemical (PEC) activity and fair thermodynamic stability toward water oxidation reaction. The results showed that the composite semiconductor's photoelectrochemical properties were much superior to pristine g-C3N4 or In2O3. The optimized 5.0 wt% g-C3N4/In2O3 composite shows the best photocurrent output of 1.3 mA cm(-2) vs Ag/AgCl at 1.2 V for water oxidation reaction having bath composition of 0.1 M Na2SO4, maintained at pH 7 using PBS under 35 mW cm(-2) irradiation. The Mott-Schottky analysis under electrochemical impedance spectroscopy indicates ntype semiconductivity of the as-prepared composite semiconductors. In addition, the action spectra show similar to 48% incident photon to current conversion efficiency (IPCE) for the optimized photoanode. The photocatalytic properties of the photocatalyst were assessed through photodegradation of methylene blue (MB) under UV-visible light irradiation, which follows first-order kinetics. The photodegradation rate constant of MB for g-C3N4 (5.0 wt %)/In2O3 is 0.0190 min(-1), which is almost doubled as compared to pristine In2O3 (rate constant 0.0110 min(-1)). The durability of the laboratory-prepared photoanodes in the PEC process was also investigated. The improved PEC performances derived from the transport of excited electrons from the conduction band of g-C3N4 to In2O3.

Nanosize nickel hydroxide decorated 2-napthalene sulfonic acid-doped polyaniline nanotubes nanocomposites (Ni(OH)(2)@NSA-PANI NCs) were successfully developed for the catalytic reduction of aromatic nitro compounds. The Ni(OH)(2)@NSA-PANI NCs were synthesised by depositing Ni(OH)(2) nanoparticles onto 2-napthalene sulfonic acid doped PANI nanotubes surface. The resulting material was characterized using field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), powder X-ray diffraction (P-XRD), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The prepared nanocomposite showed a remarkable ability to catalytically hydrogenate aromatic nitro compounds using sodium borohydride (NaBH4) as hydrogen source in aqueous medium at room temperature. Kinetic studies were performed using 4-nitrophenol (4-NP) as the model substrate, using the Langmuir-Hinshelwood model. The catalyst showed pseudo-first-order kinetics, with rate constants estimated between 0.08287 and 0.3649 min(-1). Catalyst recyclability without reduced activity was demonstrated over 10 successive cycles. The optimised nanocomposite catalyst demonstrated a low activation energy barrier towards 4-NP reduction. (C) 2020 Elsevier Inc. All rights reserved.

In the present work, raw waste material obtained from polluting dried tree fibres (raw TF) as a source of natural carbon was used for the removal of contaminating copper ions in water. Through two sequential steps of oxidation, carbonaceous adsorbent materials were obtained. Namely, tree fibre activated carbon treated with sulphuric acid (TFSA) and oxidised activated carbon modified using Hummer's method (TFHM). These materials were then characterized using techniques such as SEM, TEM, XRD, FTIR, XPS, TGA, Raman, and BET. The surface areas were found to have an increase from 0, 0.3109 and 55.0107 m2/g for raw TF, TFSA, and TFHM, respectively. The carbonaceous adsorbents were then used in batch adsorption studies for the removal of copper ions in a test water solution. The maximum adsorption capacities determined by non-linear estimation models at the optimum pH 6, were 11.04 and 80.19 mg/g for TFSA and TFHM, respectively. Furthermore, copper is known to facilitate many organic transformations such as reduction and cyclisation, thus, the spent carbonaceous adsorbents were re-used in cyclocondensation and catalytic reduction reactions to avoid discarding these into the environment and creating secondary pollutants. The initial catalytic studies of cyclocondensation of benzamine lead to 96% and 98% yield of desired product via recrystallization while catalytic reduction of 4-nitrophenol was obtained 92% within 22 min.