Enhanced perfluorooctanoic acid (PFOA) degradation by electrochemical activation of peroxydisulfate (PDS) during electrooxidation for water treatment.

Improved treatment of per- and polyfluoroalkyl substances (PFAS) in water is critically important in light of the proposed United States Environmental Protection Agency (USEPA) drinking water regulations at ng L-1 levels. The addition of peroxymonosulfate (PMS) during electrooxidation (EO) can remove and destroy PFAS, but ng L-1 levels have not been tested, and PMS itself can be toxic. The objective of this research was to test peroxydisulfate (PDS, an alternative to PMS) activation by boron-doped diamond (BDD) electrodes for perfluorooctanoic acid (PFOA) degradation. The influence of PDS concentration, temperature, and environmental water matrix effects, and PFOA concentration on PDS-EO performance were systematically examined. Batch reactor experiments revealed that 99 % of PFOA was degraded and 69 % defluorination was achieved, confirming PFOA mineralization. Scavenging experiments implied that sulfate radicals (SO4-) and hydroxyl radicals (HO) played a more important role for PFOA degradation than 1O2 or electrons (e-). Further identification of PFOA degradation and transformation products by liquid chromatography-mass spectrometry (LC-MS) analysis established plausible PFOA degradation pathways. The analysis corroborates that direct electron transfers at the electrode initiate PFOA oxidation and SO4- improves overall treatment by cleaving the CC bond between the C7F15 and COOH moieties in PFOA, leading to possible products such as C7F15 and F-. The perfluoroalkyl radicals can be oxidized by SO4- and HO, resulting in the formation of shorter chain perfluorocarboxylic acids (e.g., perfluorobutanoic acid [PFBA]), with eventual mineralization to CO2 and F-. At an environmentally relevant low initial concentration of 100 ng L-1 PFOA, 99 % degradation was achieved. The degradation of PFOA was slightly affected by the water matrix as less removal was observed in an environmental river water sample (91 %) compared to tests conducted in Milli-Q water (99 %). Overall, EO with PDS provided a destructive approach for the elimination of PFOA.

Facile fabrication of amorphous Al/Fe based metal-organic framework as effective heterogeneous fenton catalyst for environmental remediation.

This study presents a facile preparation and durable amorphous Fe and Al-based MOF nanoplate (AlFe-BTC MOFs) catalyst with notable stability in Fenton reactions. Rigorous characterization using XRD, HR-TEM, and BET confirms the amorphous nature of the synthesized AlFe-BTC MOFs, revealing mesopores (3.4 nm diameter), a substantial surface area (232 m2/g), and a pore volume of 0.69 cc/g. XPS analysis delineates distinct Al2p and Fe2p binding energy values, signifying specific chemical bonding. FE-SEM elemental mapping elucidates the distinctive distribution of Fe and Al within the framework of AlFe-BTC MOFs. In catalytic activity testing, the amorphous AlFe-BTC MOFs exhibited outstanding performance, achieving complete degradation of Methylene blue (MB) dye and 78% TOC removal over 45 min of treatment under mild reaction conditions. The catalyst's durability was assessed, revealing about 75% TOC removal and complete dye decomposition over five successive recycles, with less than 1 mg/L of Fe and Al leaching. UV-Vis spectra revealed the destruction of MB dye over multiple recycling studies. Based on this finding, the amorphous AlFe-BTC MOF nanoplates emerge as a promising solution for efficient dye removal from industrial wastewater, underscoring their potential in advanced environmental remediation processes.

Graphene materials in pollution trace detection and environmental improvement.

Water scarcity is a pressing issue experienced in numerous countries and is expected to become increasingly critical in the future. Anthropogenic activities such as mining, agriculture, industries, and domestic waste discharge toxic contaminants into natural water bodies, causing pollution. Addressing these environmental crises requires tackling the challenge of removing pollutants from water. Graphene oxide (GO), a form of graphene functionalized with oxygen-containing chemical groups, has recently garnered renewed interest due to its exceptional properties. These properties include a large surface area, mechanical stability, and adjustable electrical and optical characteristics. Additionally, surface functional groups like hydroxyl, epoxy, and carboxyl groups make GO an outstanding candidate for interacting with other materials or molecules. Because of its expanded structural diversity and enhanced overall properties, GO and its composites hold significant promise for a wide range of applications in energy storage, conversion, and environmental protection. These applications encompass hydrogen storage materials, photocatalysts for water splitting, the removal of air pollutants, and water purification. Serving as electrode materials for various lithium batteries and supercapacitors. Graphene-based materials, including graphene, graphene oxide, reduced graphene oxide, graphene polymer nanocomposites, and graphene nanoparticle metal hybrids, have emerged as valuable tools in energy and environmental remediation technologies. This review article provides an overview of the significant impact of graphene-based materials in various areas. Regarding energy-related topics, this article explores the applications of graphene-based materials in supercapacitors, lithium-ion batteries, and catalysts for fuel cells. Additionally, the article investigates recent advancements in detecting and treating persistent organic pollutants (POPs) and heavy metals using nanomaterials. The article also discusses recent developments in creating innovative nanomaterials, nanostructures, and treatment methods for addressing POPs and heavy metals in water. It aims to present the field's current state and will be a valuable resource for individuals interested in nanomaterials and related materials.

A novel approach to environmental pollution management/remediation techniques using derived advanced materials.

The carbon dioxide (CO2) crisis is one of the world's most urgent issues. Meeting the worldwide targets set for CO2 capture and storage (CCS) is crucial. Because it may significantly reduce energy consumption compared to traditional amine-based adsorption capture, adsorption dependant CO2 capture is regarded as one of the most hopeful techniques in this paradigm. The expansion of unique, critical edge adsorbent materials has received most of the research attention to date, with the main objective of improving adsorption capacity and lifespan while lowering the temperature of adsorption, thereby lowering the energy demand of sorbent revival. There are specific materials needed for each step of the carbon cycle, including capture, regeneration, and conversion. The potential and efficiency of metal-organic frameworks (MOFs) in overcoming this obstacle have recently been proven through research. In this study, we pinpoint MOFs' precise structural and chemical characteristics that have contributed to their high capture capacity, effective regeneration and separation processes, and efficient catalytic conversions. As prospective materials for the next generation of energy storage and conversion applications, carbon-based compounds like graphene, carbon nanotubes, and fullerenes are receiving a lot of interest. Their distinctive physicochemical characteristics make them suitable for these popular study topics, including structural stability and flexibility, high porosity, and customizable physicochemical traits. It is possible to precisely design the interior of MOFs to include coordinatively unsaturated metal sites, certain heteroatoms, covalent functionalization, various building unit interactions, and integrated nanoscale metal catalysts. This is essential for the creation of MOFs with improved performance. Utilizing the accuracy of MOF chemistry, more complicated materials must be built to handle selectivity, capacity, and conversion all at once to achieve a comprehensive solution. This review summarizes, the most recent developments in adsorption-based CO2 combustion capture, the CO2 adsorption capacities of various classes of solid sorbents, and the significance of advanced carbon nanomaterials for environmental remediation and energy conversion. This review also addresses the difficulties and potential of developing carbon-based electrodes for energy conversion and storage applications.

A Flexible Anti-Biofilm Hygiene Coating for Water Devices.

Biofilm is a microbiome complex comprising different bacterial colonies that typically adhere to device surfaces in water, which causes serious medical issues such as indwelling infections and outbreaks. Here, we developed a non-nanoparticle, flexible anti-biofilm hygiene coating consisting of lithocholic acid (LCA), zinc pyrithione (Zn), and cinnamaldehyde (Cn) (named as LCA-Zn-Cn) that largely prevents the bacteria adhesion to various water device surfaces such as stainless steel and glass through a synergistic mechanism. The existing chelated groups on LCA and Cn attract plenty of bacteria via hydrophobic interaction. Both the bactericidal reaction by grafting biocidal groups from both LCA and Cn and the bacteriostatic reaction by inhibiting cell division via zinc ions (Zn) lead to a largely improved bacteria/biofilm prevention. The antibacterial performance was assessed by using the JIS Z 2801/ISO 22196 method. The designed LCA-Zn-Cn coating displayed log10 reduction of 4.23 (99.9% reduction) of E. coli and log10 reduction of 3.51 (99.8% reduction) of E. faecalis on stainless steel, which are much higher than the control samples, demonstrating a promising colonization inhibition. In parallel, the polysulfone encapsulated beads also showed >99% reduction efficiency in batch and >97-98% reduction efficiency in continuous column tests using the Lake Michigan water. Due to the strong cross-linked configuration, the coating still showed >90.9% bacterial reduction after 3000 abrasion cycles and over 99.9% bacteria reduction after a high flow velocity of 1.99 m/s test, which confirmed the enhanced mechanical durability. By applying either spray or dip-coating, the designed polymer composite can be coated on a variety of irregular water devices with mass production using an auto-controlled robot arm.

A comprehensive review on strategic study of cellulase producing marine actinobacteria for biofuel applications.

Every year, 180 billion tonnes of cellulose are produced by plants as waste biomass after the cultivation of the desired product. One of the smart and effective ways to utilize this biomass rather than burn it is to utilize the biomass to adequately meet the energy needs with the help of microbial cellulase that can catalytically convert the cellulose into simple sugar units. Marine actinobacteria is one of the plentiful gram-positive bacteria known for its industrial application as it can produce multienzyme cellulase with high thermal tolerance, pH stability and high resistant towards metal ions and salt concentration, along with other antimicrobial properties. Highly stable cellulase obtained from marine actinobacteria will convert the cellulose biomass into glucose, which is the precursor for biofuel production. This review will provide a comprehensive outlook of various strategic applications of cellulase from marine actinobacteria which can facilitate the breakdown of lignocellulosic biomass to bioenergy with respect to its characteristics based on the location/environment that the organism was collected and its screening strategies followed by adopted methodologies to mine the novel cellulase genome and enhance the production, thereby increasing the activity of cellulase continued by effective immobilization on novel substrates for the multiple usage of cellulase along with the industrial applications.

Hydrothermally constructed AgWO4-rGO nanocomposites as an electrode enhancer for ultrasensitive electrochemical detection of hazardous herbicide crisquat.

The advancements in electrode materials with high efficiency has been prioritized to effectively monitor the presence of harmful pesticides concerning the environment. In such a way, we hydrothermally constructed a hybrid AgWO4-rGO nanocomposites for the rapid electrochemical detection of crisquat (CQT). The structural, compositional, morphological and topographical characterization for AgWO4-rGO nanocomposites is thoroughly performed to understand its electrocatalytic properties. The AgWO4-rGO nanocomposites are used as an electrode enhancer (rGO@AgWO4/GCE) for the electrochemical investigations towards CQT detection. The results indicated that the rGO@AgWO4/GCE possessed an excellent catalytic activity with a wide linear detection range 1-1108 µM coupled with an ultrasensitive limit of detection (LOD) 0.0661 µM for electrochemical CQT detection. The rGO@AgWO4/GCE CQT sensor also expressed remarkable sensitivity of 0.6306 µAµM-1cm-2 in addition to good selectivity and reproducibility. Furthermore, the commercial CQT, river water, tap water and washed vegetable water are used as a representative for real world analysis using rGO@AgWO4/GCE and results are highly appreciable for the real time CQT detection. Our work proposes a novel hybrid rGO@AgWO4 nanocomposites reinforced electrodes for ultra-trace level CQT detection with good reliability and can be advocated for real time detection of pesticides.

Photocatalytic degradation of perfluoroalkyl substances in water by using a duo-functional tri-metallic-oxide hybrid catalyst.

The recalcitrant nature of perfluoroalkyl substances (PFASs) urges scientists to discover solutions to permanently remove PFAS contaminations from water with less energy in contrast to incineration. Herein, a duo-functional tri-metallic-oxide (f-TMO) hybrid photocatalyst was developed via a facile process, which displayed both high adsorption capacity and high defluorination rate of a series of PFASs including PFOA, PFOS, PFHpA, PFHxA and PFBA due to the generated holes/electrons (h+/e-) and multi-radicals such as O2•- and SO4•-. Particularly the Langmuir adsorption capacities up to 827.84 and 714.46 mg g-1 along with the adsorption efficiency of 99.8% and 99.4% for PFOS and PFOA were respectively achieved. A defluorination ratio of as high as 74.8% with PFOA and a ratio up to 67.6% with PFOS were respectively received. Over 98% PFOA molecules were degraded within as fast as 15 min under initial concentrations ranging from 1 ppb to 1000 ppb, which demonstrates an excellent degradation kinetics. As for the sulfonic acid of PFOS, an as high as 95.5% degradation efficiency was obtained within 300 min. The degradation rates were 4.5 mg L-1 h-1 for PFOA and 0.54 mg L-1 h-1 for PFOS, respectively. In parallel, the f-TMO photocatalyst still exhibited a >96.2% degradation efficiency after eight regeneration cycles. The high physical adsorption capacity and high defluorination rate make this f-TMO catalyst promising applications in removing various PFASs from a broad range of residential and industrial water systems.

Fabricating BiOI nanostructures armed catalytic strips for selective electrochemical and SERS detection of pesticide in polluted water.

We have constructed a dual mode catalytic strip equipped with 2D BiOI nanostructures and deployed for dual mode detection sensing of hazardous trichlorophenol (TCP). Synthesized BiOI nanostructures are investigated for its crystal architecture, morphology and chemical composition. The BiOI are loaded onto the catalytic strips with the assistance of gravity offered drying process. The BiOI nanostructures offers a very less charge transfer resistance indicating its superior catalytic properties upon the electrochemical impedance studies. It reflected on providing an excellent limit of detection (LOD) and linear sensing range for TCP in electrochemical mode. For SERS, a thin plasmonic Au layer is sputter coated on BiOI equipped catalytic strips (Au@BiOI) for the TCP detection. An impressive enhancement factor of 107 is obtained for SERS detection of TCP with good LOD of 10-10 M. Fabricated dual mode BiOI based strips are thoroughly examined for operational stability and performance in real time conditions. The fabricated high performance dual mode platform for the detection of hazardous pesticides appears to be a promising prospect for the on-the-spot investigation.

Synthesis of recyclable GO/Cu3(BTC)2/Fe3O4 hybrid nanocomposites with enhanced photocatalytic degradation of aflatoxin B1.

This study evaluated the photocatalytic performance of the activated carbon assisted GO/Cu3(BTC)2/Fe3O4 photocatalyst for aflatoxin B1 (AFB1) degradation under ultraviolet light. The nanocomposite was characterized by Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption-desorption. The numerous factors influencing the degradation efficiency of AFB1 including catalyst dose, pH importance, and contact time were also probed. The elevated degradation performance of AFB1 by 99% was due to a larger surface area and improved GO/Cu3(BTC)2/Fe3O4 photocatalyst. The degradation process followed a pseudo-first-order kinetic model. Moreover, it is possible to quickly isolate the catalyst from the solution and retain successful operation. In the degradation of AFB1, the hole(h+) and the hydroxyl radicals(OH) were found to play a significant role. These studies showed that GO/Cu3(BTC)2/Fe3O4 has high capturing capacity and photoactivity synergy, thereby offering a quick effect, and green solution to AFB1 degradation.

Influence of 2D template-assisted (SBA-15) metal oxide Co3O4 for pseudocapacitive and dye degradation application.

Cobalt oxide (Co3O4) is a low-cost material exhibiting excellent physicochemical and photocatalytic properties indicating its potential use for next-generation eco-friendly energy storage and photocatalytic degradation applications. In this study, Co3O4 nanoarcs were synthesized using SBA-15 as a template by microwave-assisted method to form an S15/m-Co3O4 product. Characterization was done by low and wide-angle X-Ray diffraction, and Fourier transformed infra-red spectroscopic studies confirming the presence of S15/m-Co3O4. Scanning Electron Microscope images proved the agglomerated nanotube and nanoarcs like the structure of SBA-15 and S15/m- Co3O4, respectively. Electrochemical studies included cyclic voltammetry, charge/discharge, retention capacity, and electron impedance spectroscopy studies in a 3-electrode system. S15/m-Co3O4 nanoarcs, as the electrode material, was revealed to have a specific capacity of 87.5 C/g in 1 M KOH solution. Upon running 1000 cycles, the material had excellent capacity retention of 87%. The S15/m-Co3O4 product also underwent photocatalytic degradation studies. The Rhodamine R6G dye degradation by S15/m-Co3O4 under UV irradiation exhibited a high degradation percentage of 97.7%, following the first-order kinetics. S15/m-Co3O4 has proven to be biocompatible and can be used to enhance supercapacitors which are an ideal alternative to conventional batteries for energy storage applications. Thus, the data produced proves S15/m-Co3O4 nanoarcs is an excellent electrode material for pseudocapacitive application and a catalyst for photocatalytic degradation of dye molecules.

Nanomaterials as adsorbents for As(III) and As(V) removal from water: A review.

Freshwater demand will rise in the next couple of decades, with an increase in worldwide population growth and industrial development. The development activities, on one side, have increased the freshwater demand. However, the ground water has been degraded. Among the various organic and inorganic contaminants, arsenic is one of the most toxic elements. Arsenic contamination in ground waters is a major issue worldwide, especially in South and Southeast Asia. Various methods have been applied to provide a remedy to arsenic contamination, including adsorption, ion exchange, oxidation, coagulation-precipitation and filtration, and membrane filtration. Out of these methods, adsorption of As(III)/As(V) using nanomaterials and biopolymers has been used on a wide scale. The present review focuses on recently used nanomaterials and biopolymer composites for As(III)/As(V) sorptive removal. As(III)/As(V) adsorption mechanisms have been explored for various sorbents. The impacts of environmental factors such as pH and co-existing ions on As(III)/As(V) removal, have been discussed. Comparison of various nanosorbents and biopolymer composites for As(III)/As(V) adsorption and regeneration of exhausted materials has been included. Overall, this review will be useful to understand the sorption mechanisms involved in As(III)/As(V) removal by nanomaterials and biopolymer composites and their comparative sorption performances.

Ultrasensitive electrochemical detection of furazolidone in biological samples using 1D-2D BiVO4@MoS2 hierarchical nano-heterojunction composites armed electrodes.

In this work, the hydrothermally synthesized of BiVO4@MoS2 hierarchical nano-heterojunction composite is employed as a novel electrocatalyst for electrochemical sensing of Furazolidone (FZE) drug by modifying the glassy carbon electrodes (GCE). The Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy are used to thoroughly investigate the functional groups, vibrational modes, crystal structure, elemental composition and surface topography of the heterojunction composite. The physical characterization results revealed the successful construction of 1D-2D BiVO4@MoS2 hierarchical nano-heterojunction composite. When these unique architectures are reinforced on GCE surface, we achieved an enhanced electroactive surface area of 0.154 cm2. The electrochemical performance of 1D-2D BiVO4@MoS2 is examined though cyclic voltammetry and differential pulse voltammetry (DPV) analysis. The BiVO4@MoS2 composites exhibited an excellent electrocatalytic activity in sensing of FZE with superior linear detection ranges of 0.01-14 and 14-614 µM. The limit of detection (LOD) of the BiVO4@MoS2 based sensor is determined to be 2.9 nM which is far superior than other reported FZE sensors. Consequently, it is evident from the investigation that the BiVO4@MoS2 based FZE sensor can be recommended for analyzing real time samples like human urine and blood serum with appreciable recovery.

Incorporation of SiO2 functionalized gC3N4 sheets with TiO2 nanoparticles to enhance the anticorrosion performance of metal specimens in aggressive Cl- environment.

Nowadays, carbon-based nano-structured materials are widely preferred for composite coating as anti-corrosive reinforcement mainly due to its enhanced physical, chemical and mechanical properties. Herein we develop highly efficient Graphitic carbon nitride-Silica-Titania (gC3N4/SiO2/TiO2) ternary nanocomposite are synthesized and it is used as a nanofillers in the corrosive protection layer on the proposed metal specimen (i.e., mild steel specimen) in an aggressive chloride environment. Size, structural and morphological analysis were analysed for the confirmation of presence of particles. gC3N4 is currently earning quite drastic attention, owing to its affordable cost compared to carbon nanotubes and other carbon-based materials, when gC3N4 incorporated with SiO2 and TiO2, the composite matrix greatly improves the mechanical strength of the coating mixture. XRD, XPS, EDS analysis projects excellent formation and presence of the ternary nanocomposites. The particles are well-dispersed in epoxy and organic resin and deposited on the mildsteel panels and it is examined using various surface and structural characterization techniques. The obtained results are very encouraging and the ternary composite coatings can be recommended for real world applications.

Biogenic Synthesis of Iron Oxide Nanoparticles Using Enterococcus faecalis: Adsorption of Hexavalent Chromium from Aqueous Solution and In Vitro Cytotoxicity Analysis.

The biological synthesis of nanoparticles is emerging as a potential method for nanoparticle synthesis due to its non-toxicity and simplicity. In the present study, a bacterium resistant to heavy metals was isolated from a metal-contaminated site and we aimed to report the synthesis of Fe3O4 nanoparticles via co-precipitation using bacterial exopolysaccharides (EPS) derived from Enterococcus faecalis_RMSN6 strains. A three-variable Box-Behnken design was used for determining the optimal conditions of the Fe3O4 NPs synthesis process. The synthesized Fe3O4 NPs were thoroughly characterized through multiple analytical techniques such as XRD, UV-Visible spectroscopy, FTIR spectroscopy and finally SEM analysis to understand the surface morphology. Fe3O4 NPs were then probed for the Cr(VI) ion adsorption studies. The important parameters such as optimization of initial concentration of Cr(VI) ions, effects of contact time, pH of the solution and contact time on quantity of Cr(VI) adsorbed were studied in detail. The maximum adsorption capacity of the nanoparticles was found to be 98.03 mg/g. The nanoparticles could retain up to 73% of their efficiency of chromium removal for up to 5 cycles. Additionally, prepared Fe3O4 NPs in the concentration were subjected to cytotoxicity studies using an MTT assay. The investigations using Fe3O4 NPs displayed a substantial dose-dependent effect on the A594 cells. The research elucidates that the Fe3O4 NPs synthesized from EPS of E. faecalis_RMSN6 can be used for the removal of heavy metal contaminants from wastewater.

Detection, Contamination, Toxicity, and Prevention Methods of Ochratoxins: An Update Review.

Ochratoxins (OTs) with nephrotoxic, immunosuppressive, teratogenic, and carcinogenic properties are thermostable fungal subordinate metabolites. OTs contamination can occur before or after harvesting, during the processing, packing, distribution, and storage of food. Mold development and mycotoxin contamination can occur in any crop or cereal that has not been stored properly for long periods of time and is subjected to high levels of humidity and temperature. Ochratoxin A (OTA) presents a significant health threat to creatures and individuals. There is also a concern of how human interaction with OTA will also express the remains of OTA from feedstuffs into animal-derived items. Numerous approaches have been studied for the reduction of the OTA content in agronomic products. These methods can be classified into two major classes: inhibition of OTA adulteration and decontamination or detoxification of food. A description of the various mycotoxins, the organism responsible for the development of mycotoxins, and their adverse effects are given. In the current paper, the incidence of OTA in various fodder and food materials is discussed, which is accompanied by a brief overview of the OTA mode of synthesis, physicochemical properties, toxic effects of various types of ochratoxins, and OTA decontamination adaptation methods. To our knowledge, we are the first to report on the structure of many naturally accessible OTAs and OTA metabolism. Finally, this paper seeks to be insightful and draw attention to dangerous OTA, which is too frequently neglected and overlooked in farm duplication from the list of discrepancy studies.

Clean approach for chromium removal in aqueous environments and role of nanomaterials in bioremediation: Present research and future perspective.

Chromium is an insidious ecological pollutant that is of huge value for its toxicity. The existing ecological objective to lower the heights of toxic materials in marine systems and to stimulate the existing water to recycle after suitable treatment of wastewater. Chromium is a hazard element that appears in discharges of numerous industries that must be diminished to accomplish the goals. Nearly all of the findings described in the literature related to the usage of various materials such as fungal, algal, bacterial biomass, and nanomaterials for chromium adsorption. The current work evaluates the findings of research commenced in the preceding on the use of a variety of adsorbents to decrease chromium concentrations in contaminated waters. This review article focuses on the issue of chromium contamination, its chemistry, causes, consequences, biological agent remediation techniques, and the detailed process of chromium detoxification in microbial cells. It also lists a description of the in situ and ex situ chromium bioremediation methods used. This can help design more effective Cr(VI) removal methods, thus bridging the difference between laboratory discoveries and industrial chromium remediation applications.

Immobilization of cellulase enzymes on nano and micro-materials for breakdown of cellulose for biofuel production-a narrative review.

Cellulose is a very abundant polymer that is found in nature. Cellulose has been used as a raw material for production of biofuels for many years. However, there are multiple processing steps that are required so that cellulose can be used as a raw material for biofuel production. One of the most important steps is the breakdown of cellulose into intermediate sugars which can then be a viable substrate for biofuel production. Cellulases are enzymes which play a role in the catalysis of the breakdown of cellulose into glucose. Nanomaterials and micromaterials have been gaining a lot of attention over the past few years for its potential in immobilizing enzymes for industrial procedures. Immobilization of enzymes on these nanomaterials has been observed to be of great value due to the improvement in thermal stability, pH stability, regenerative capacity, increase in activity and the reusability of enzymes. Similarly, there have been multiple reports of cellulase enzymes being immobilized on various nanoparticles. The immobilization of these cellulase enzymes have resulted in very efficient processing and provide a great and economic solution for the processing of cellulose for biofuel production. Hence in this paper, we review and discuss the various advantages and disadvantages of enzymes on various available nanomaterials.

Synthesis of a copper (II) metal-organic framework for photocatalytic degradation of rhodamine B dye in water.

The Cu(II) metal-organic frameworks (MOFs) based on 1,3,5-benzenetricarboxylic acid (Cu3(BTC)2) was synthesized by the hydrothermal method. The synthesized Cu3(BTC)2 exhibited pyramid-shaped morphology and showing an average specific area of 32.16 m2 g-1. The Cu3(BTC)2 photocatalysts were characterized using Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), field emission scanning electron microscopy-energy-dispersive X-ray spectroscopy (FESEM-EDX), UV-Vis diffusive reflectance spectra, and Brunauer-Emmett-Teller (BET). The photocatalytic activity of Cu3(BTC)2 was examined on Rhodamine B (RhB) degradation under visible light irradiation. The outcomes displayed exceedingly enhanced photocatalytic activity under visible light. In addition, its recyclability was also confirmed for multiple cycles. The easiness of construction and high photocatalytic performance of Cu3(BTC)2 photocatalysts can be capable in environmental applications to treat water contamination.

Ultrasound-assisted synthesis of mixed calcium magnesium oxide (CaMgO2) nanoflakes for photocatalytic degradation of methylene blue.

In the present study, mixed calcium magnesium oxide (CaMgO2) nanoflakes were synthesized using an ultrasound-assisted co-precipitation method. The physicochemical, structural and functional properties and elemental composition of the nanoflakes had been characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), High-resolution transmission electron microscopy (HR-TEM), Fourier Transform Infrared spectroscopy (FTIR), UV-VIS spectroscopy, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Moreover, the photocatalytic actions of the nanoflakes were evaluated by the removal rates of methylene blue (MB) and p-nitrophenol (4-NP) under UV irradiation at room temperature. SEM-EDS studies revealed that the nanoflakes consisted of mixed oxide such as magnesium oxide (MgO) and calcium oxide (CaO) particles. The size of the nanoflakes was found to be in the range of 10-30 nm and the average size was 25 nm as confirmed by HR-TEM analysis. XRD revealed that the standard crystal size was calculated to be 25 nm. The synthesized nanoflakes had a strong photocatalytic activity for methylene blue (MB) and p-nitrophenol (4-NP) degradation in the presence of H2O2 under UV light irradiation within 60 min and 30 min, respectively. Hence, the present study proposes that the CaMgO2 nanoflakes can be employed for the removal of dyes from wastewater.