Researchers in the field of photocatalysis are interested in finding a solution to the problem of charge transfer and recombination in photodegradation mechanisms. The ideal photoactive catalyst would be inexpensive, environmentally friendly, easily manufactured, and highly efficient. Graphitic carbon nitride (g-CN) and metal oxide (MOx) based nanocomposites (g-CN/MOx) are among the photocatalysts that provide the best results in terms of charge transfer capacity, redox capabilities, and charge recombination inhibition.
View Article and Find Full Text PDFLignocellulosic biomass contains lignin, an aromatic and oxygenated substance and a potential method for lignin utilization is achieved through catalytic conversion into useful phenolic and aromatic monomers. The application of monometallic catalysts for lignin hydrogenolysis reaction remains one of the major reasons for the underutilization of lignin to produce valuable chemicals. Monometallic catalysts have many limitations such as limited catalytic sites for interacting with different lignin linkages, poor catalytic activity, low lignin conversion, and low product selectivity.
View Article and Find Full Text PDFDriven by the urgent need for a solution to tackle the surge of rice husk (RH) and waste frying oil (WFO) waste accumulation at a global scale, this report highlights the use of calcium silicates (CS) extracted from acid-pre-treated rice husk ash (RHA) for free fatty acid (FFA) removal from WFO as conventional RHA shows limited FFA adsorption performance. A novel alkaline earth silicate extraction method from acid-pre-treated RHA was outlined. The structural and behavioural attributes of the synthesised CS were identified through BET, SEM-EDS, and XRD analyses and compared to those of RHA.
View Article and Find Full Text PDFThis study provides a systematic analysis of the transport and magnetophoretic behavior of nanoscale zerovalent iron (nZVI) particles, both bare and surface functionalized by poly(ethylene glycol) (PEG) and carboxymethyl cellulose (CMC), after undergoing a chemical reaction. Here, a simple and well-investigated chemical reaction of methyl orange (MO) degradation by nZVI was used as a model reaction system, and the sand column transport and low-gradient magnetophoretic profiles of the nanoparticles were measured before and after the reaction. The results were compared over time and analyzed in the context of extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to understand the particle interactions involved.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
June 2023
This study investigated the effect of different CoO-based catalysts on the catalytic decomposition of nitrous oxide (NO) and on nitric oxide (NO) conversion. The experiments were carried out using various reaction temperatures, alkaline solutions, pH, mixing conditions, aging times, space velocities, impregnation loads, and compounds. The results showed that CoO catalysts prepared by precipitation methods have the highest catalytic activity and NO conversion, even at low reaction temperatures, while the commercial nano and powder forms of CoO (CS) have the lowest performance.
View Article and Find Full Text PDFThe penicillin derivative amoxicillin (AMX) plays an important role in treating various types of infections caused by bacteria. However, excessive use of AMX may have negative health effects. Therefore, it is of utmost importance to detect and quantify the AMX in pharmaceutical drugs, biological fluids, and environmental samples with high sensitivity.
View Article and Find Full Text PDFThe seed extract of Abelmoschus esculentus (AE), also known as Okra, was used as a source of reducing and capping agents to synthesized biogenic titanium dioxide nanoparticles (TiO NPs) due to its rich flavonoid contents. The synthesized AE-TiO nanoparticles were further evaluated by the effect of loading of TiO NPs and irradiation time on the photocatalytic degradation of methylene blue dye. The synthesized TiO NPs were then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), Fourier transformed infrared (FTIR) spectroscopy, Raman spectra, UV-visible spectrophotometry, and particle size distribution (PSD).
View Article and Find Full Text PDFIn this study, a novel cellulose/Ag/TiO nanocomposite was successfully synthesized via the hydrothermal method. The cellulose extracted from oil palm empty fruit bunch (OPEFB) could address the disposal issue created by OPEFB biomass. Characterization studies such as FESEM, EDX, HRTEM, XRD, FTIR, UV-Vis DRS, PL, XPS, and surface analysis were conducted.
View Article and Find Full Text PDFIron-doped titanium dioxide loaded on activated carbon (Fe-TiO/AC) was successfully synthesized from oil palm empty fruit bunch (OPEFB) using sol-gel method. The properties of the synthesized pure TiO, Fe-doped TiO, AC, TiO/AC and Fe-TiO/AC were examined by various techniques such as field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and nitrogen adsorption-desorption analyses at 77 K. FE-SEM revealed that Fe-doped TiO particles were dispersed homogeneously on the AC surface.
View Article and Find Full Text PDFNowadays, the current synthesis techniques used in industrial production of nanoparticles have been generally regarded as nonenvironmentally friendly. Consequently, the biosynthesis approach has been proposed as an alternative to reduce the usage of hazardous chemical compounds and harsh reaction conditions in the production of nanoparticles. In this work, pure, iron (Fe)-doped and silver (Ag)-doped zinc oxide (ZnO) nanoparticles were successfully synthesized through the green route using Clitoria ternatea Linn.
View Article and Find Full Text PDFThis study is focused on nanocrystalline cellulose (NCC) flakes for methylene blue (MB) removal via adsorption. NCC flakes exhibit a high adsorption capacity (188.7 mg/g fixed at 0.
View Article and Find Full Text PDFThis study investigated the behavior and mechanisms of cross-linked Durio zibethinus seed starch (CDSS) flocculants for landfill leachate treatment. A physical-chemical treatment method of coagulation-flocculation process and starch modification were implemented in treating stabilized leachate from Matang Landfill, Perak, Malaysia. In practical, the removal performance of color, COD, suspended solid and turbidity for CDSS flocculants were evaluated by combining with primary coagulant of polyaluminium chloride (PAC).
View Article and Find Full Text PDFThis paper critically reviews the impacts of supplementing trace elements on the anaerobic digestion performance. The in-depth knowledge of trace elements as micronutrients and metalloenzyme components justifies trace element supplementation into the anaerobic digestion system. Most of the earlier studies reported that trace elements addition at (sub)optimum dosages had positive impacts mainly longer term on digester stability with greater organic matter degradation, low volatile fatty acids (VFA) concentration and higher biogas production.
View Article and Find Full Text PDFAdsorption performance of chitosan (CS) hydrogel beads was investigated after impregnation of CS with hexadecylamine (HDA) as a cationic surfactant, for the elimination of reactive blue 4 (RB4) from wastewater. The CS/HDA beads formed with 3.8% HDA were the most effective adsorbent.
View Article and Find Full Text PDFThe adsorption behavior of chitosan (CS) beads modified with 3-aminopropyl triethoxysilane (APTES) for the removal of reactive blue 4 (RB4) in batch studies has been investigated. The effects of modification conditions, such as the APTES concentration, temperature and reaction time on RB4 removal, were studied. The adsorbent prepared at a concentration of 2 wt% APTES for 8h at 50 °C was the most effective one for RB4 adsorption.
View Article and Find Full Text PDFHighly effective WO3/ZnO nanorods (NRs) were synthesized via a hydrothermal-deposition method for degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) under natural sunlight. The structural properties of WO3/ZnO NRs such as morphology, crystal structure, porous properties and light absorption characteristics were investigated in detail. The X-ray diffraction and X-ray photoelectron spectroscopy results indicated that the prepared samples were two-phase photocatalysts consisted of WO3 and ZnO NRs.
View Article and Find Full Text PDFChitosan based adsorbents have received a lot of attention for adsorption of dyes. Various modifications of this polysaccharide have been investigated to improve the adsorption properties as well as mechanical and physical characteristics of chitosan. This review paper discusses major research topics related to chitosan and its derivatives for application in the removal of dyes from water.
View Article and Find Full Text PDFRev Environ Contam Toxicol
September 2014
Many industries discharge untreated wastewater into the environment. Heavy metals from many industrial processes end up as hazardous pollutants of wastewaters.Heavy metal pollution has increased in recent decades and there is a growing concern for the public health risk they may pose.
View Article and Find Full Text PDFThe use of pseudo-infinite methanol in increasing the rate of esterification and transesterification reactions was studied using oil palm trunk (OPT) and sugarcane bagasse (SCB) derived solid acid catalysts. The catalysts were prepared by incomplete carbonisation at 400°C for 8h, followed by sulfonation at 150°C for 15h and characterised using TGA/DTA, XRD, FT-IR, SEM-EDS, EA and titrimetric determinations of acid sites. Under optimal reaction conditions, the process demonstrated rapid esterification of palmitic acid, with FAME yields of 93% and 94% in 45min for OPT and SCB catalysts, respectively.
View Article and Find Full Text PDFSonocatalytic degradation of acid red B (ARB) dye was investigated using Fe doped zeolite Y catalysts with the assistance of low frequency (20 kHz) ultrasonic irradiation. Low concentration of Fe ions from different precursors was loaded onto the zeolite using wet impregnation method. Catalytic degradation of ARB dye was found to be accelerated by the reaction between Fe (II) and Fe (III) ions and hydrogen peroxide (H2O2) generated in situ by the ultrasound-mediated dissociation of water molecules.
View Article and Find Full Text PDFIn the work presented here, photocatalytic systems using TiO2 and ZnO suspensions were utilized to evaluate the degradation of resorcinol (ReOH). The effects of catalyst concentration and solution pH were investigated and optimized using multivariate analysis based on response surface methodology. The results indicated that ZnO showed greater degradation and mineralization activities compared to TiO2 under optimized conditions.
View Article and Find Full Text PDFFe-doped titanium dioxide (TiO(2)) nanotubes were prepared using sol-gel followed by hydrothermal methods and characterized using various methods. The sonocatalytic activity was evaluated based on oxidation of Rhodamine B under ultrasonic irradiation. Iron ions (Fe(3+)) might incorporate into the lattice and intercalated in the interlayer spaces of TiO(2) nanotubes.
View Article and Find Full Text PDFA new heterogeneous catalyst for sonocatalytic degradation of amaranth dye in water was synthesized by introducing titania into the pores of zeolite (NaY) through ion exchange method while Fe (III) was immobilized on the encapsulated titanium via impregnation method. XRD results could not detect any peaks for titanium oxide or Fe(2)O(3) due to its low loading. The UV-vis analysis proved a blue shift toward shorter wavelength after the loading of Ti into NaY while a red shift was detected after the loading of Fe into the encapsulated titanium.
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