Synthesis of fibrous silica tantalum (FSTa) for photooxidative desulphurization

The photooxidative desulphurization (PODS) of dibenzothiophene (DBT) was examined under visible light using fibrous silica tantalum (FSTa), tantalum oxide doped fibrous silica (Ta/KCC-1) and commercial tantalum oxide (Ta2O5). FSTa was synthetized using hydrothermal method, while Ta/KCC-1 was obtained via a wet impregnation method. The catalysts were examined by field emission scanning electron microscopy (FESEM), X-ray Diffraction (XRD) and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). It was shown that the FSTa possesses the highest photocatalytic performance (70.2%), due to its fibrous structure, well-dispersion of Ta, as well as its narrower band gap. These traits impact on the photocatalysis by promoting the deposition of the DBT on the catalyst, allowing the efficient transfer of charge carrier and preventing the electron-hole recombination

Effect of Fe2O3 loading on CuO/CNT photocatalyst for degradation of p-Chloroaniline

Chloroaniline and its derivatives are generated from industrial chemical manufacturing processes including agricultural chemical, azo dyes and pigments, pesticides and herbicides. These compounds are found to be toxic and dangerous to aquatic and human life. Hence, their discharge into the environment must be regulated. Photocatalytic degradation is one of a promising method to remove such compounds due to its safety, low energy consumption and high efficiency. In this study, the research focused on the effect of iron oxides (Fe2O3) loading (5-50 wt%) on copper-carbon nanotubes (CuO/CNT) photocatalyst for degradation of p-chloroaniline (PCA) under visible light irradiation. The synthesized catalysts were characterized using Fourier Transform Infrared Spectroscopy to analyze its functional groups. Besides Fe2O3 loading, various parameters such as effect of PCA pH solution (3-11), catalyst dosage (0.125- 0.625 g L-1) as well as PCA initial concentration (10-100 mg L-1) were investigated. It was found that the highest degradation (75 %) of 10 mg L-1 PCA was achieved using 0.325 g L-1 10 wt% Fe2O3/50 wt% CuO/CNT at pH 7. Kinetics study showed that the PCA photodegradation followed pseudo first-order Langmuir-Hinshelwood model. It is believed that the Fe2O3/CuO/CNT can be a potential photocatalyst for degrading organics pollutant efficiently

Amine (Polyethyleneimine)-modified solid adsorbent for CO2 capture

The increase in the concentration of carbon dioxide (CO2) gas in the atmosphere has led to various severe negative consequences. There are numerous methods for the reduction of CO2 that have been introduced such as chemical and physical absorption, organic liquid scrubbing, amine-based absorption, etc. Adsorption by using solid adsorbents is one of the promising methods that has been widely studied by researchers. The performance of the adsorbents can be enhanced by functionalized with diverse types of promoters. This review is discussing the performance of polyethyleneimine (PEI) as a promoter towards the adsorption of CO2. To achieve high effective PEI-adsorbents, the percentage of PEI amine loading, type of porous support, temperature, and different flow conditions are among the important parameters that need to be considered. The chemical stability of PEI can be improved through modification crosslinking of PEI. Hence in this review, the effect of amine loading, porous support, temperature, slow condition and crosslinking of PEI to its CO2 adsorption performance is observed

A contemporary assessment on composite titania onto graphitic carbon nitride-based catalyst as photocatalyst

Titanium dioxide (TiO2) has drawn widespread interest by researchers as a precious semiconductor that is responsive towards photodegradation of various pollutants. This catalyst has its own limitations such as fast electron-hole recombination, wide band gap, and can only be utilised under ultraviolet (UV) region. In order to overcome these problems, the addition of a metal-free dopant is a common practice to prevent electron-hole recombination and enhance photodegradation under visible light. Among various types of metal-free catalysts, carbon nitride material has received much attention due to its numerous benefits such as good in terms of physical and chemical strength, as well as an attractive electronic band combined with a band gap (2.7 eV). This review summarised recent works in the development of titania incorporated with graphitic carbon nitride (g-C3N4) for enhanced photocatalytic activity

Beneficial interaction of copper oxide and fibrous silica for enhanced photocatalytic desulphurization

Photocatalytic desulphurization (PDS) is considered as a promising technique to remove hazardous sulphur compounds from fuel oil due to its high catalytic activity, safety, low energy consumption, and low cost. In this work, fibrous silica KCC-1 was synthesized by hydrothermal method followed by incorporation of CuO by electrolysis. The catalyst was used for PDS of dibenzothiophene (DBT). The presence of bicontinuous concentric lamellar morphology with uniform spherical shape was confirmed by FESEM analysis. The phase and crystallinity of the catalysts was investigated by XRD, while the band gap energy was determined by UV-Vis DRS. The PDS performance of CuO/KCC-1 was compared with KCC-1, CuO/SiO2 and SiO2. It was observed that the photoactivity of CuO/KCC-1 was higher than other catalysts (62.6%), which is mainly due to its fibrous morphology and appropriate band gap energy, as well as synergistic role of both CuO and KCC-1. This fibrous type catalyst could be a promising candidate for environmental purification specifically in the sulphur removal

A brief on tetraethylenepentamine (TEPA) functionalized-adsorbents in CO2 capture application

Among numerous carbon capture technologies, adsorption is considered one of the most effective approaches to reduce carbon dioxide (CO2) emissions in the atmosphere. Various modification approaches of adsorbents have been introduced to enhance the CO2 adsorption ability. Recently, an amine such as tetraethylenepentamine (TEPA) has been extensively used as an adsorbent's promoter because of its high amine density, low viscosity, low cost, and low toxicity properties. This has added an advantage to the adsorbent in terms of economical and environmentally benign. Therefore, it is important to provide the latest review on TEPA-functionalized adsorbents, specifically on the effects of TEPA functionalization, different TEPA loading, diverse adsorption conditions, as well as the structure of adsorbents towards the CO2 adsorption capacity. Different adsorption conditions over a wide range of adsorption temperatures were thoroughly discussed and several recommendations for future studies were also been proposed

Effect of carbon-interaction on structure-photoactivity of Cu doped amorphous TiO2 catalysts for visible-light-oriented oxidative desulphurization of dibenzothiophene

Amorphous TiO2 (AT) was successfully prepared via the sol-gel technique, using different titanium sources followed by incorporation of copper via the electrochemical method to give CuO/TiO2 (CAT) catalysts. The catalysts were characterized via XRD, N2 physisorption, FTIR, TEM, EDX, XPS, ESR and UV–Vis DRS. The results verified that the use of different titanium precursors have profound effect on the physicochemical properties of the AT catalysts. Further one-pot self-doping carbon from titanium precursor during the addition of copper could greatly enhanced the photocatalytic activity of CAT on the oxidative desulphurization of dibenzothiophene (DBT). 15 CATTBOT exhibited the best performance mainly due to the narrowest band gap and higher numbers of O–Ti–C and Ti–O–C bonds, as well as appropriate amount of Ti3+ surface defects (TSD). These abovementioned properties offered good mobility of electron-hole pairs and/or trap the electrons for enhancement of photoactivity under irradiation of visible light. Kinetic studies showed that the photocatalytic oxidative desulphurization of DBT followed the pseudo-first order Langmuir-Hinshelwood model, where the adsorption was the controlling step. It is believed that these results could contribute to the synthesis of various supported catalysts for numerous applications specifically in removal of sulphur containing compounds in fuel oils

Directing the amount of CNTs in CuO–CNT catalysts for enhanced adsorption-oriented visible-light-responsive photodegradation of p-chloroaniline

Copper oxide (CuO, 10–90 wt%) was loaded onto carbon nanotubes (CNTs) by electrosynthesis method. The catalysts (CuO/CNT) were characterized by XRD, nitrogen adsorption–desorption, ESR, FTIR, Raman, and XPS spectroscopy. The results indicated that a lower amount of CuO was dispersed well on the CNT, while higher loading was agglomerated, producing large-size crystallites, hence resulting in lower specific surface area. Adsorption studies revealed that the isotherms are fitted well with the Langmuir model. Moreover, the n value that was obtained from Freundlich model indicated that adsorption process is chemisorption. Photodegradation of p-chloroaniline (PCA) under visible light irradiation demonstrated that the 50 wt% CuO/CNT catalyst gave the highest degradation (97%). It was concluded that C–N moieties of PCA were chemisorbed on the catalyst prior to photodegradation, while the Cu–O–C bonds, surface defects and oxygen vacancies were the main active site in enhancing the subsequent photodegradation. The kinetics of photodegradation were correlated with pseudo-first-order model, verifying the surface reaction was the controlling step. Remarkable mineralization results of PCA were attained by TOC (89.1%) and BOD5 (50.7%). It was also evidenced that the catalyst has a good potential toward degradation of various endocrine disruption compounds

A review on exploration of fe2o3 photocatalyst towards degradation ofdyes and organic contaminants

Photocatalytic degradation is among the promising technology for removal of various dyes and organic contaminants from environment owing to its excellent catalytic activity, low energy utilization, and low cost. As one of potential photocatalysts, Fe2O3 has emerged as an important material for degradation of numerous dyes and organic contaminants caused by its tolerable band gap, wide harvesting of visible light, good stability and recyclability. The present review thoroughly summarized the classification, synthesis route of Fe2O3 with different morphologies, and several modifications of Fe2O3 for improved photocatalytic performance. These include the incorporation with supporting materials, formation of heterojunction with other semiconductor photocatalysts, as well as the fabrication of Z-scheme. Explicitly, the other photocatalytic applications of Fe2O3, including for removal of heavy metals, reduction of CO2, evolution of H2, and N2 fixation are also deliberately discussed to further highlight the huge potential of this catalyst. Moreover, the prospects and future challenges are also comprised to expose the unscrutinized criteria of Fe2O3 photocatalyst. This review aims to contribute a knowledge transfer for providing more information on the potential of Fe2O3 photocatalyst. In the meantime, it might give an idea for utilization of this photocatalyst in other environmental remediation application

Fabrication of fibrous silica zinc (FSZn) composite for enhanced photocatalytic desulphurization

Novel fibrous silica zinc (FSZnIS) catalyst was synthesized by in-situ hydrothermal-microwave method and the catalyst was analyzed by X-ray Diffraction (XRD), N2 physisorption, Field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR), UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS) and photoluminescence (PL). The catalyst was employed in photocatalytic desulphurization of dibenzothiophene (DBT) in model fuel. The performance of FSZnIS was compared with bare fibrous silica (KCC-1), commercial ZnO and fibrous silica zinc prepared by impregnation method (FSZnIP). The photoactivity towards catalytic desulphurization of DBT is in the following order: FSZnIS (88.9%) > FSZnIP (62.4%) > KCC-1 (53.9%) > ZnO (44.4%). The best performance was achieved using 0.375 gL−1 of FSZnIS catalyst over 100 mgL−1 DBT in model fuel. This is predominantly due to the well distribution of ZnO on KCC-1, high surface area (411.2 m2 g−1), high number of Si–O–Zn bonds, appropriate band gap energy (2.95 eV), and proficient charge separation. These criteria mutually encouraged effective harvesting of visible light (420 nm) and good mobility of charge carriers for enhanced visible light driven performance. A kinetics study determined by Langmuir–Hinshelwood model demonstrated that the photodesulphurization obeyed the pseudo-first-order and adsorption was the rate-limiting step