Russian Journal of Applied Chemistry最新文献

Abstract

The aim of the work is to investigate the use of synthetic doped catalyst in the removal of benzene, toluene, and xylene (BTX) from petroleum wastewater by photocatalyst process in a circular column reactor. Fe₂O₃-doped anatase TiO₂ with 10 nm average grain size was synthesized by the impregnation method. The prepared doped catalyst was characterized using energy-dispersive X-ray (EDS), scanning electron microscopy (SEM), Surface Area Analysis using the Brunauer–Emmett–Teller (BET), Fourier transforms infrared spectroscopy (FTIR) beforehand with XRD. Then it is evaluated in a photocatalyst process A which was done in a circular column with dimensions of 70 mm diameter and 390 mm height, under visible light. The study also shows the influence of pH, light intensity and residence time on the BTX removal. The experiment was carried out under different values of pH (3‒11), light intensity 14‒42 W and irradiation time 30‒120 min. The results show that the maximum removal efficiency was 90% when pH 6.5, 42 W light intensity and after 120 min. The kinetic model as well as Adsorption isotherm were also studied.

Abstract

Flux decline is one of the most significant defies ultrafiltration (UF) must overcome. One viable approach to address this issue involves the implementation of nano-additives into the membrane matrix. In this research, the potential of chamomile leaf nanoparticles (Chm NPs) as an eco-friendly material for use in UF membrane synthesis was explored. To better understand the impact of Chm on the production of PES UF membranes, a range of membranes were created by introducing varying amounts of Chm into the casting solution. The produced membranes were thoroughly evaluated, focusing on aspects such as porosity, pore size, hydrophilicity, membrane morphology, and UF performance. Manufactured PES/Chm membranes demonstrated significantly increased permeate water flux (PWF) (up to 367 L/m² h), which was three times that of the pristine PES membrane (126 L/m² h). Beside Methylene Blue dye (MB) rejection, it was obtained a high removal percent of about 94 %. Additionally, decreased contact angle (C.A.) for modified membranes (47%), compared with pristine PES membranes, all these results led to enhance the membrane permeate flux and rejection. The utilization of chamomile as a novel environmentally friendly addition holds significant potential in the production of UF membranes for wastewater treatment.

The results of studies on determination of the ignition delay time of hypergolic low-toxicity (“green”) propellants with high-test hydrogen peroxide as an oxidizer are discussed. The use of liquid and solid fuels containing compounds that catalyze the hydrogen peroxide decomposition (manganese and copper salts) or actively react with hydrogen peroxide (e.g., NaBH₄) allows preparation of propellants with the ignition delay time shorter than 20 ms, which allows using these propellants in liquid or hybrid rocket engines. The use of ionic liquids as a fuel in most cases also requires introducing promoters.

Depressor additives based on stearyl methacrylate homopolymer and its copolymers with various monomers (butyl methacrylate, methacrylic acid esters of С₁₀–С₁₄ fraction, maleic anhydride) were synthesized in the presence of reversible addition–fragmentation chain-transfer agents allowing control of the molecular-weight characteristics of the polymers. The low-temperature properties of the diesel fuel containing additives based on the above polymers were evaluated. The copolymers exhibit the better depressor effect compared to the stearyl methacrylate homopolymer. Modification of the stearyl methacrylate–maleic anhydride copolymer with 1-octanol was performed. The modified additive well competes in performance with the modern commercial depressor-dispersing additives and can decrease the congealing point of hydrotreated diesel fuels by 20°С.

Abstract

The air quality in petroleum refineries is one of the most critical factors in the petroleum refining processes. Several parameters in the air usually have a direct influence on human health and the environment, including poisoning gases, vapors, and particulate matter (PMs). In the present study, the air quality was evaluated in petroleum refineries sites to provide more understanding of the effect of the presence of such polluted materials on the environment and the operator’s health in the refinery. It was found that petroleum refineries produce a series of fatal compounds such as sulfur compounds hydrocarbons (gases and vapors), and PM_0.1, PM_2.5, and PM₁₀. All these materials have a solid impact on human health. It was found that they used many types of air filters, such as personal masks or central air filtration units reducing the concentration of such polluted material dramatically. Also, the results showed that the used crude oil (API) and sulfur contents are the main two important factors that reflect air quality. The high API crude oil with low sulfur compounds produces low polluted material in the air. Moreover, it was found that the modern refineries that used Euro-5 (eco-friendly design) produced fewer emissions with a cleaner environment in comparison with old versions of the refining design.

Abstract

In this work a fully analytical approach for atomic force microscopy (AFM) (non-contact mode) is proposed to determine surface roughness, morphology, and topography of two commercial CoMo-γAl₂O₃ catalysts (Ketjenfine 124-3E and Ketjenfine 165) that are used in hydrotreating process (HTP) in Iraqi refineries. All parameters of the AFM image (amplitude, hybrid and spatial parameters) were discussed with a new insight and a detailed description of how the nano-particles were built in and distributed in hypothetical multi layers based on mathematical calculations of volume and surface area based on regarding that each individual grain has a sphere-like shape of a specific diameter. A clear relationship between grain number and average diameter was noticed, due to the increase in grain average diameter of KF124-3E (143.47 nm) comparing to that of KF165 (120.21) leads to make the density of grain distribution for the latter is greater than that of KF124. Surface area of total grains of Ketjenfine 124-3E and Ketjenfine 165 were 8 919 303.275 and 8 031 267.809 nm², respectively. Higher roughness average (S_a) value of catalyst KF165 (18.4 nm) means the reactants will have more opportunity for complete reaction. Root mean square (S_q) values were 8.16 nm for KF124-3E and 21.5 nm for KF165 indicating that KF165 is rougher than KF124-3E. Surface skewness of KF124-3E and KF165 were 0.00031, –0.168, respectively. For both hydrotreating catalysts the surface kurtosis value (S_ku) was about ≤2.0 and the distribution curves is Platykurtic. Root means square slope (S_dq) for KF165 catalyst is 1.31 nm^–1, which is approximately four times greater than that of KF124-3E (0.35 nm^–1) indicating that KF165 has rougher surface profile.

Abstract

Recent advances have drawn the attention of many researchers in the creation of innovative catalysts that are not only effective but also cost-effective and ecologically benign. The large similarity between the geopolymers and zeolitic materials makes geopolymers suitable for catalytic applications. This research works on preparing geopolymer catalysts utilizing two different types of Iraqi kaolin (white and red kaolin) with six different mixes. Additionally, the hydrochloric acid (2M) treatment was conducted on the geopolymer base kaolin to increase surface area, and catalytic activity (improving the adsorption capacity) makes geopolymer more suitable for catalyst applications. The characterization of the geopolymer involved techniques such as XRD, XRF, FTIR, and BET. FTIR results showed changes in OH group structures (increase Brønsted & Lewis acid sites) essential for catalyst applications. XRD results indicated the presence of zeolite and Annite-phase along with amorphous phases. BET analysis of large increased surface area and pore size in acid-treated geopolymers. This research suggests the potential for improving inexpensive geopolymer catalysts, opening the door to cost-effective, sustainable, and high-performance catalysts for use in industries requiring porous materials and heavy oil processing, and paving the way for a greener and more environmentally conscious future.

Abstract

The production of biodiesel from macroalgae using base catalysts is gaining interest in sustainable energy. Biodiesel generation from macroalgae uses several methods, but this research focuses on base catalysts. The paper begins with a detailed overview of bio-diesel production and its usefulness as an eco-friendly fossil fuel alternative. It then examines macroalgae and their role in biodiesel production. Macroalgae’s abundance, rapid growth, and lack of rivalry with food crops are all discussed in the article. Additionally, it solves extraction efficiency and production cost constraints. The review focuses on alkaline catalysts for macroalgae biodiesel production. The benefits of solid-base catalysts over liquid-base catalysts make them suitable biodiesel catalysts. These benefits include increased process efficiency, catalyst recovery, waste reduction, and environmental impact reduction. Overall, this offers an extensive examination of the process of producing biodiesel from macroalgae with base catalysts. This study emphasises the capacity of macroalgae as a renewable resource and offers valuable information on the methods to enhance efficiency and address environmental concerns for the effective use of this technology.

The morphology of latexes (aqueous solutions of spherical polystyrene particles with carboxyl and amino groups on the surface) was studied using UV and IR spectroscopy, scanning electron microscopy (SEM), and dynamic light scattering (DLS). The histograms of the size distribution of polystyrene particles were built using SEM images of the latexes. Similar size distribution curves for polystyrene latexes were obtained using IR and UV spectroscopy. The data of IR and UV spectroscopy and independent methods such as SEM and DLS are in good agreement.

The effect that additions of fluorinated alcohols to an aqueous solution of polyvinyl alcohol exert on the rheological and physicochemical properties of elastic cryocomposites obtained after the freezing–thawing cycle was studied. The elastic modulus of the ternary cryogel (polyvinyl alcohol–water–1,1,7-trihydrododecafluoroheptyl alcohol) is 2 times higher than that of the binary cryogel (polyvinyl alcohol–water). With an increase in the molecular mass of fluorinated alcohols, the elastic modulus of cryogels increases from 65 to 80 kPa. The presence of fluorinated alcohols in the cryogel matrix imparts hydrophobic properties to the material, and the dried samples, in contrast to the cryogels without additives, do not burn.