Use Of Hydrochloric Acid Research Articles

Synthesis and characterization of chitosan for medical applications: A review.

Chitosan has gained considerable recognition within the field of medical applications due to its exceptional biocompatibility and diverse range of properties. Nevertheless, prior reviews have primarily focused on its applications, offering limited insights into its source materials. Hence, there arises a compelling need for a comprehensive review that encompasses the entire chitin and chitosan life cycle: from the source of chitin and chitosan, extraction methods, and specific medical applications, to the various techniques employed in evaluating chitosan's properties. This all-encompassing review delves into the critical aspects of chitin and chitosan extraction, with a strong emphasis on the utilization of natural raw materials. It elucidates the various sources of these raw materials, highlighting their abundance and accessibility. Furthermore, a meticulous examination of extraction methods reveals the prevalent use of hydrochloric acid (HCl) in the demineralization process, alongside citric, formic, and phosphoric acids. Based on current review information, these acids constitute a substantial 69.2% of utilization, surpassing other mentioned acids. Of notable importance, the review underscores the essential parameters for medical-grade chitosan. It advocates for a degree of deacetylation (DDA) falling within the range of 85%-95%, minimal protein content <1%, ash content <2%, and moisture content <10%. In conclusion, these crucial factors contribute to the understanding of Chitosan's production for medical applications, paving the way for advancements in biomedical research and development.

Abstract A032: The role of ASIC2 and calcium influx in epithelial ovarian cancer pathogenesis

Abstract Objective: Inflammation associated with incessant ovulation plays a key role in epithelial ovarian cancer (EOC) pathogenesis. Ion channels, such as acid-sensing ion channel-2 or ASIC2 is known to be upregulated in inflammatory conditions and may play a role in calcium ion dysregulation. Here, we describe a potential relationship between ASIC2 and intracellular calcium levels in EOC development and progression. Methods: EOC cell lines OVCAR-8, ES-2 and SKOV-3 were grown to sub-confluence prior to experimentation. Global extracellular pH was changed with the use of hydrochloric acid (HCl) over various time points at hours (h): 2 h, 4 h, 8 h, 12 h and 24 h. ASIC2 expression was subsequently measured via western blot. Intracellular pH was measured with the use of pH-sensitive pHrodo red dye. Cytosolic pH was determined across all cell lines at baseline and after treatment with a known ASIC2 inhibitor: Diminazene (10 μM) over 30 minutes. Intracellular calcium levels were measured with a Fluo Calcium Indicator at baseline and with similar ASIC2 inhibition. Live cell imaging was utilized on a Nikon A1r confocal microscope. Results: Changing global, extracellular pH to 6.0 and 6.5 across various time points from 2-24 h did not affect ASIC2 protein expression via western blot analysis. We then utilized a pH-sensitive assay to determine whether intracellular pH changes were associated with ASIC2 expression. Interestingly, intracellular pH was noted to increase across most cell lines with ASIC2 inhibition via Diminazene treatment. There was a statistically significant increase in pH in ES2 and OVCAR8 cell lines. Because ASIC2 is known to result in influx of various ions, assessment of intracellular calcium levels was performed first after 30 minutes of Diminazene treatment. There was a corresponding significant increase in intracellular calcium levels in ES2 cells after ASIC2 inhibition. And there was a small trend, albeit not significant, toward a similar increase across SKOV-3 and OVCAR-8 cells. Conclusion: There seems to be a role for ASIC2 in EOC, particularly in the context of inflammation as noted by changes in intracellular pH levels. It is likely that ASIC2 may mediate changes in intracellular calcium signaling and promote tumorigenesis in ovarian cancer. Citation Format: Tanvi Joshi, Annelise Wilhite, Sagar Chokshi, Mary Howard Singleton, Jennifer Scalici, Kevin Lee. The role of ASIC2 and calcium influx in epithelial ovarian cancer pathogenesis [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A032.

Kinetics and mechanism of selective leaching of bismuth from molybdenite and bismuthinite mixed ore

In the conventional beneficiation process for handling mixed ore containing molybdenite and bismuthinite, the co-extraction issues involving molybdenum and bismuth, exemplified by mutual content of molybdenite and bismuthinite, may lead to the shutdown of the production line. Under acidic conditions, Bi3+ and Cl− can form stable coordination complex anions, whereas Mo4+, Mo6+, and Cl− do not exhibit this behavior. This insight offers a novel approach for the chemical separation of molybdenum and bismuth from mixed ore using hydrochloric acid. Through a kinetic study of the hydrochloric acid leaching process applied to bismuth extraction from mixed molybdenite and bismuthinite ore, we have investigated various factors that influence leaching efficiency, such as stirring speed, particle size, acid concentration, and reaction temperature. Experimental results and computational results have revealed that the apparent activation energy is 56 kJ mol−1. The kinetic analysis suggests that the leaching process is governed by the product layer diffusion model. Moreover, the use of hydrochloric acid in leaching the mixed ore is shown to alter the surface structure, thereby increasing the effective reaction area. This, in turn, leads to improved leaching efficiency and enhances the overall leaching process.

Prevalence and risk factors for hand eczema among professional hospital cleaners in Denmark: A cross-sectional questionnaire-based study.

Professional cleaners are commonly affected by hand eczema (HE) due to wet work and exposure to cleaning products in the work environment. To investigate (1) the prevalence of HE in a group of professional hospital cleaners, (2) the association of HE with various comorbidities and self-reported signs/symptoms of skin lesions and (3) the association of HE with various occupational and personal risk factors in the same population. A cross-sectional questionnaire-based study including all cleaners working in three hospitals in Denmark. The questionnaire was composed of 35 questions. Prevalence is reported using proportions with 95% confidence intervals and compared using difference of proportions and Fisher's exact test. A total of 122 out of 180 cleaners (response rate = 68%) participated in this study. The self-reported lifetime prevalence of HE among the cleaners was 30.3%, while the 1-year prevalence was 18.9%. HE was significantly associated with a history of atopic diseases. There was a significant correlation between having HE, and self-reported redness and itch of the hands in the last 12 months, as well as the use of hydrochloric acid ≥4 days/week during the last 12 months. Logistic regression analysis found HE significantly associated with washing hands ≥20 times during a working day and a history of atopic dermatitis. Cleaners are at an elevated risk of developing HE. More focus on education/information regarding the prevention and treatment of HE is necessary for the cleaning profession. Self-reported redness and itching of the hands may be a useful prediction of HE in cleaners.

Determination of arsenic and antimony by atmospheric pressure glow discharge portable emission spectrometer with solid acid hydride generation

In this work, the use of solid acid hydride generation (HG) for the simultaneous determination of As and Sb in environmental water samples by miniaturized atmospheric pressure glow discharge plasma optical emission spectrometer (APGD-OES) was evaluated. It was found that HG with the use of sulfamic acid tablets can achieve comparable sensitivity with conventional HCl-KBH4 for As and Sb determination by APGD-OES, which avoids the safety issue encountered in the use of hydrochloric acid and greatly facilitates field analysis. Under optimal conditions, the obtained detection limits (LODs) are as low as 1.26 μg L−1 for As and 0.72 μg L−1 for Sb, respectively. Moreover, it offers good repeatability, where the relative standard deviations (RSDs) are less than 2.5%. The accuracy of the proposed method was validated by the analysis of simulated natural water reference samples. Furthermore, it has been successfully applied to the determination of tap water, pond water, and hot spring samples. All these results clearly demonstrate the proposed simple, cost-effective and field-deployable method provides a promising approach for the field analysis of As and Sb.

Accelerated Synthesis of Borophane (HB) Sheets through HCl-Assisted Ion-Exchange Reaction with YCrB4

We present an enhanced method for synthesizing sheets of borophane. Despite the challenges associated with low efficiency, we discovered that incorporating hydrochloric acid into the ion-exchange reaction significantly improved the production yield from 20% to over 50%. After a thorough examination of the reaction, we gained insight into the underlying mechanisms and found that the use of hydrochloric acid provides two key benefits: accelerated production of borophene and isolation of high-purity products. This method has the potential to pave the way for the production of novel topological 2D materials with potential industrial applications.

Pengaruh Penggunaan Asam Klorida terhadap Rendemen, Kadar Air, dan Kadar Abu Gelatin Ceker Itik (Anas platyrhynchos Javanica)

Gelatine is a product produced from collagen hydrolysis. Solvents that can be use in the manufacture of gelatin are acidic and basic solutions. The acid used in this experiment is hydrochloric acid (HCl). The quality factor of gelatine can be determined from the amount of yield, moisture content, and ash content. The quality of gelatine also depends on the concentration of hydrochloric acid solution. This experiment aims to determine the effect of HCl concentration on yield, moisture content, and ash content of gelatine from duck feet, to find the concentration of HCl that can produce the best quality of gelatine from duck feet, and to find the form of tendency between treatments of HCl concentration on yield, moisture content and ash content of gelatine from duck feet. The experiment was conducted experimentally using Completely Randomized Design (CRD). The treatments used were HCl concentration P1 (4%), P2 (6%), and P3 (8%), with six times repetation so that there were 18 experimental units. The results showed that the use of hydrochloric acid 6% can gave the best quality of gelatine from duck feet with 8,04% yield, 5,99% moisture content, and 3,98% ash content.

Конденсация Михаэля 2-(4-карбоксибензилиден)-3,4-дигидронафтален-1(2Н)-она с метиленактивными соединениями в направленном синтезе О-гетероциклических гибридных систем

Approaches to the design of new hybrid polyoxaheterocyclic compounds based on the interaction of 2-(4-carboxybenzylidene)-3,4- dihydronaphthalene-1(2H)-one with methylene active compounds of the 2H-chromen-2-one series – 3 -(1,3-dioxobutan-1-yl)-2H-chromen- 2-one and 4-hydroxy-2H-chromen-2-one, as well as their carbocyclic analogue – 1,3-indanedione under various conditions have been considered. It has been revealed for the first time that during the reaction of the studied chalcone with 3-acetoacetyl-2H-chromen-2-one in a piperidine medium, followed by treatment with acetic acid, the hybrid acetate 7-(4-carboxyphenyl)-8-oxo-5,8-dihydro-6H-benzo[h] chromeno[3,2-b]xanthylium is formed. It has been found that the formation of such a hybrid structure with the participation of 1,3-indanedione in the Michael condensation as the methylene component under similar conditions is not possible. In this case, the competitive nucleophilic addition of piperidine at the arylidene fragment with the formation of 4-((1,2,3,4-tetrahydro-1-oxonaphthalen-2-yl)(piperidin- 1-yl)-methyl)benzoic acid is predominant. It has been shown that the condensed adduct of arylidene dihydronaphthalene-1(2H)-one with 1,3-indanedione arises by refluxing the reagents in pyridine. The use of hydrochloric acid in the isolation of the reaction product contributes to the aromatization of the resulting dihydrochromene ring, which ultimately leads to the chloride 7-(4-carboxyphenyl)-8-oxo-6,8-dihydro- 5H-benzo[h]indeno[1,2- b] chromen-13-ilium. A similar trend is observed when 4-hydroxy-2H-chromen-2-one is introduced into the transformation under study. It has been found for the first time that when the reaction is carried out in glacial acetic acid with the addition of piperidine as a catalyst, the latter also acts as an azanucleophile and competitively binds to the reaction center of the substrate. Replacing the solvent with pyridine leads to the formation of a hybrid system, 4-(6-oxo-8,9-dihydro-6H,7H-benzo[h]chromeno[4,3-b]chromen-7-yl)- benzoic acid. In this case, salt formation after treatment with hydrochloric acid is not observed. Thus, in the course of the study, a new synthetic approach to the formation of hybrid chromene, xanthene systems has been considered. The observed salt formation can be the factor in increasing the bioavailability of newly synthesized compounds.

Adaptation of the alginate production process for the brown alga Sargassum horridum (Fucales: Sargassaceae)

The genus Sargassum is a brown alga which is abundant in México, in the Gulf of California and the Caribbean Sea. The large biomass could be used to production of alginate, a polysaccharide with properties which allow it to form a thick solution or gels for different industries, such as for pharmaceutical and food products. The alginate production process may have some modifications, depending on the type of alga that is used as raw material, reducing water consumption and increasing the alginate yield and quality. In this research, the amount of water and reagents was optimized, reducing the volumes in the production process, based on the volumes used to process the giant kelp Macrocystis pyrifera. Hydration was reduced from 1 : 10 to 1 : 4 (part of alga : volume of chemical), acid pre-extraction from 1 : 10 to 1 : 5, extraction from 1 : 16 to 1 : 10, and dilution from 1 : 55 to 1 : 15; bleaching was improved from very dark brown to pale brown. The main reason that reduction is possible is that Sargassum has a more rigid cell wall than Macrocystis, absorbing less water and producing less viscosity. Although the alginate viscosity is relatively low, some applications require low viscosity solutions. However, the gel strength reached up to 1906 g cm−2, which may compete with other alginates to produce gelling products. To avoid the use of hydrochloric acid and decrease the contamination of wastewater in the process, the acid pre-extraction stage was changed for a neutral pre-cooking stage, resulting in an increase of the alginate yield from 8.3 % to 13.5 %; the viscosity was normally kept low, but the gel strength increased up to 2400 g cm−2.

Corrosion inhibition of steel by selected homologues of the class 3-alkyl-5-amino-1H-1,2,4-triazoles in acidic media

The use of hydrochloric acid in the treatment of the bottomhole formation zone leads to the significant corrosion of metals, as well as hydrogen and chloride stress cracking of pump compressor pipes. In order to solve this problem, corrosion inhibitors are added to a hydrochloric acid solution. This article presents the results of a study of the anticorrosive activity of a number of derivatives of the class of 3-alkyl-5-amino-1H-1,2,4-triazole under the conditions of hydrochloric acid corrosion of low-carbon steel. During the study, selected 3-alkyl-5-amino-1H-1,2,4-triazoles were synthesized. Their structure was confirmed and proved using NMR spectroscopy and HPLC/MS spectrometry. Regularities of the anticorrosive ction of the investigated compounds have been established using polarization electrochemical studies and gravimetric direct corrosion tests. Corrosion rates, inhibition coefficients and degrees of protection have been calculated for all inhibitors. The probable mechanism of the inhibitory action of the studied compounds has been substantiated using quantum chemical calculations based on the density functional theory using the Gaussian program. It was shown that the structure of the alkyl substituents has the greatest effect on the inhibitory activity of the studied compounds. The mechanism was proposed for the adsorption of the inhibitor, which explained the increase in protective properties with an increase in the length of the alkyl substituent. The high hydrophobicity of the aliphatic fragment, not involved in the chemisorption process, additionally prevents the acid solution from contacting the metal surface, while the heterocyclic moiety ensures the sorption of the inhibitor on the metal surface. As a result, it was shown that derivatives of the homologous series of 3-alkyl-5-aminotriazole are suitable as inhibitors of acid corrosion of ST-3 steel. The minimum length of a hydrocarbon radical at which significant inhibitory activity was observed is 7 carbon atoms. Protection degrees of 65–85% were achieved when 3-heptyl-5-amino-1H-1,2,4-triazole additives at a concentration of at least 2 g/L were added to the hydrochloric acid solution.

Spectral analysis of juvenile dentin biomaterials

The experiments in optical evaluation of biomaterials taken from juvenile dentin have been made using the Raman spectroscopy method. It was shown that juvenile teeth lose their mineral components and preserve organic components in the process of demineralization with the use of hydrochloric acid.

Removal adsorption of LED industrial wastewater by after resource utilization of agricultural waste

Nowadays the market value and scope of the Light-Emitting Diode (LED) industry are increasing and the amount of waste in the process has also increased. The wastewater containing gallium (Ga) ion is also produced in the LED process, such as etching, washing, and grinding. This gallium element was very rare and valuable on the earth. In this study, the agricultural waste of pomelo peel was used to be the bioadsorbent to recycle the gallium from the gallium ion wastewater to achieve the purpose of the use of waste to recycle. According to the bioadsorption tests, the use of hydrochloric acid modified bioadsorbent of pomelo peel could achieve 96.80 % bioadsorption efficiency under the optimized condition found in this study.

Study of the mechanism of pre-burned ash leaching by hydrochloric acid

The use of hydrochloric acid for processing aluminum-containing raw materials has a number of advantages over other acids, which include: easy decomposition of aluminum compounds with the transfer of aluminum into solution; low solubility of silica in HCl, the possibility of complete separation of the solid residue without significant losses of acid, etc. The paper considers the possibility of using the method for processing ash and slag dumps accumulated in large volumes in the country. Based on the thermodynamic analysis of reactions of interaction between ash components and hydrochloric acid, the behavior of aluminum, iron and nonferrous metal compounds during leaching is studied. It was shown that the preliminary roasting of ash with calcium chloride provides a high extraction of aluminum in the solution from the cinder. Based on experimental studies, the influence of time, temperature and acid consumption on the degree of aluminum extraction into the solution has been established. At optimal conditions of leaching conducted at S:L = 1:3, T = 60 ºC, τ = 60 min extraction of aluminum in a solution as chloride amounted to 99.92 %. At the same time the extraction of silica in solid sediment due to the maximum transfer of impurities in the solution was 99.8 %. The mechanism of the leaching process is proposed. The values of activation energy and the order of the reaction, indicating the complex 3-step character of the reactions, have been calculated. It is established that the limiting stage during leaching is the dissolution of anorthite.

Systematic and Facile Analysis of Deposits Composition: Implication on Effective Treatment of Oilfield Solid Deposits

Abstract Oilfield solid deposits present the major flow assurance problems in the oil and gas industry. In general, the deposits need to be accurately identified and quantified for appropriate design and successful implementation of any treatments. However, few works have been reported on the establishment of a systematic analytical procedure. This work, for the first time, presents a systematic approach that may be used to identify and quantify the composition of oilfield solid deposits, with different analytical methods been jointly used. The X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy techniques were found very helpful in identifying the composition of the investigated oilfield solid deposit, whereas thermogravimetric analysis (TGA) and microwave induced plasma atomic emission spectroscopy (MIP-AES) were the most appropriate quantification techniques. The collected sample was found to contain mainly CaCO3 and consequently, the acid treatment method that involves the use of hydrochloric acid (HCl) solution was proposed to be the most applicable and cost-effective treatment method for its remediation. The exact amount of CaCO3 scale in the oilfield system, the concentration and volume of HCl solution required for the acid treatment method need to be precisely determined to ensure the effective treatment. We believe this well-established analytical procedure will be helpful and enlightening for identification and quantification of oilfield solid deposits and thus may facilitate the effective and efficient treatments on the undesirable deposits.

A comprehensive and updated review of studies on the oxidation of cyclohexane to produce ketone-alcohol (KA) oil

Abstract Oxidation of cyclohexane is an essential chemical reaction for the industrial manufacture of cyclohexanol and cyclohexanone. These two compounds, together known as ketone–alcohol (KA) oil, are the main feedstock for nylon 6 and nylon 6,6 productions. Several types of catalysts and reaction conditions have been used for cyclohexane oxidation. This paper presents a thorough literature review of catalytic materials used for cyclohexane oxidation to produce KA oil using oxygen, air and other oxidizing agents as well as utilizing different solvents. This review covers research and development reported over the years 2014–2020. This review aims to comprehend the type of catalysts, solvents, oxidants and other reaction parameters used for the oxidation of cyclohexane. Three types of cyclohexane oxidation processes namely thermocatalytic, photocatalytic and microwave-assisted catalytic have been reported. The results of the review showed that metal and metal oxide loaded silica catalysts performed excellently and provided high selectivity of KA oil and cyclohexane conversion. The use of peroxides is not feasible due to their high price compared to air and oxygen. Gold nanoparticles supported on silica performed with high selectivity and good conversion. The use of hydrochloric acid as an additive was found very effective to enhance the photocatalytic oxidation of cyclohexane. Water on the catalyst surface enhanced the reactivity of the photocatalysts since it helps in the generation of hydroxyl radicals.

Metal Material Resistant to Hydrochloric Acid Corrosion

Hydrochloric acid, especially when contains a certain amount of FeCl3 (or oxidizing salt such as copper chloride), is highly corrosive to chemical equipment, which will lead to problems of malignant destruction and failure. Therefore, the correct and rational selection of material is essential for the production and use of hydrochloric acid. In this paper, from the corrosion characteristics of hydrochloric acid and the factors affecting the selection of hydrochloric acid resistant materials, the metal materials resistant to hydrochloric acid corrosion are reviewed, which provides a scientific basis for material selection of alumina extraction from fly ash by acid method and other similar working conditions.

Investigating the role of mechanics in lignocellulosic biomass degradation during hydrolysis: Part II.

Lignocellulose breakdown in biorefineries is facilitated by enzymes and physical forces. Enzymes degrade and solubilize accessible lignocellulosic polymers, primarily on fiber surfaces, and make fibers physically weaker. Meanwhile physical forces acting during mechanical agitation induce tearing and cause rupture and attrition of the fibers, leading to liquefaction, that is, a less viscous hydrolysate that can be further processed in industrial settings. This study aims at understanding how mechanical agitation during enzymatic saccharification can be used to promote fiber attrition. The effects of reaction conditions, such as substrate and enzyme concentration on fiber attrition rate and hydrolysis yield were investigated. To gain insight into the fiber attrition mechanism, enzymatic hydrolysis was compared to hydrolysis by use of hydrochloric acid. Results show that fiber attrition depends on several factors concerning reactor design and operation including drum diameter, rotational speed, mixing schedule, and concentrations of fibers and enzymes. Surprisingly, different fiber attrition patterns during enzymatic and acid hydrolysis were found for similar mixing schedules. Specifically, for tumbling mixing, slow continuous mixing appears to function better than faster, intermittent mixing even for the same total number of drum revolutions. The findings indicate that reactor design and operation as well as hydrolysis conditions are key to process optimization and that detailed insights are needed to obtain fast liquefaction without sacrificing saccharification yields.

Influence Different Methods of Mechanical Activation on Yield Extractive Substances from Pine Bark

The effect pine bark activation by explosive autohydrolysis and mechanical treatment in a ball mill on the yield and properties of resinous and pectin substances and β-sitosterol was studied. Pine bark physicochemical properties after its activation by a batch of methods were studied. It was shown that the activation of pine bark by explosive autohydrolysis result in the highest increase in the yield of extractive substances. The conditions providing the highest yield of target products from the activated pine bark were determined: for resinous substances and β-sitosterol – the use of 0.5 n alkali solution; for pectin substances – the use of hydrochloric acid

Investigation of leaching kinetics of aluminum extraction from secondary aluminum dross with use of hydrochloric acid

Hydrochloric acid leaching is a good way to extract aluminum from secondary aluminum dross (SAD). However, the leaching kinetics of this process is still unclear. This study investigated the leaching kinetics of aluminum extraction from SAD by using hydrochloric acid. Leaching test results showed that the leaching rate of aluminum in SAD could reach 22% under optimal conditions. According to the analyses of X-ray fluorescence, X-ray diffraction, and scanning electron microscopy with energy-dispersive spectrometer, the components that dissolve in hydrochloric acid include metal aluminum, aluminum nitride and aluminum oxide in SAD. Kinetic studies revealed that the dissolutions of metal aluminum and aluminum oxide conformed to the 1-D diffusion-controlled model and the Avrami model, respectively. The dissolution of aluminum nitride was mainly controlled by surface chemical reaction in the contracting volume model. The activation energies of metal aluminum, aluminum oxide, and aluminum nitride in the leaching process were 6.92, 11.16, and 40.93 kJ·mol−1, respectively. The activation energy of aluminum nitride was the highest, indicating that it was the most difficult to dissolve. For process practicality, the effective decomposition of aluminum nitride could realize the maximum recovery of aluminum in SAD.

Efficient and selective photocatalytic oxidation of cyclohexane using O2 as oxidant in VOCl2 solution and mechanism insight

The efficient selective oxidation of cyclohexane to cyclohexanone and cyclohexanol (KA-oil) under mild conditions remains one of the most challenging and interesting projects in catalytic chemistry. Here, photocatalytic oxidation of cyclohexane was carried out in acetonitrile (MeCN) solution of VOCl2 under Xe lamp irradiation and pure O2 atmosphere. The results show that VOCl2 has high photocatalytic activity in pure MeCN solution, and a cyclohexane conversion of 17.8% with ca. 99% selectivity for KA-oil can be obtained after light irradiation of 4 h. It is worth noting that the use of hydrochloric acid as an additive can effectively enhance the photo-catalytic oxidation of cyclohexane, providing a cyclohexane conversion of 23.3%, which may be due to the important role of HCl in improving the light absorption, decreasing the oxidation-reduction potential of V5+/V4+ and promoting the redox process of photocatalyst. The effects of photocatalyst concentration, hydrochloric acid addition amount, O2 pressure and reaction time on photocatalytic performance were also studied. It was found that the optimization of these reaction conditions can further improve the conversion of cyclohexane and selectivity of KA-oil. A possible reaction mechanism for the photocatalytic oxidation of cyclohexane was proposed.