Inorganic Products Research Articles

Nontargeted identification and predicted toxicity of new byproducts generated from UV treatment of water containing micropollutant 2-mercaptobenzothiazole

Comprehensive identification of byproducts including intermediate transformation products (TPs) of micropollutants in source water is challenging and paramount for assessment of drinking water quality and treatment technologies. Here, we have developed a nontargeted analysis strategy coupled with computational toxicity assessment to identify indistinguishable TPs including isomers with large differences in toxicity. The new strategy was applied to study the UV treatment of water containing micropollutant 2-mercaptobenzothiazole (2-MBT), and it enabled successful identification of a total of 22 organic TPs. Particularly, the structures of nine new TPs were identified for the first time; in addition, three isomers (P2, P3, and P4) were distinguished from the toxic contaminant 2-hydroxybenzothiazole (2-OH-BT). Computational assessments indicate that estrogenic activity of the three isomers (P2-P4) is higher than that of 2-OH-BT. Mass balance study shows that the 22 organic products accounted for 70% of the 2-MBT degraded, while 30% may degrade to inorganic products. Most TPs are resistant to UV photolysis. Computational toxicity assessment predicted the TPs to increase inhibition of human thyroperoxidase activity although they have lower aquatic toxicity compared to original 2-MBT. This study emphasizes the importance of monitoring the 2-MBT photodegradation products and the overall toxicity of finished water whose production included a UV light-based treatment process.

A qualitative and semiquantitative SEM study of the morphology of the biofilm on root surfaces of human teeth with endodontic-periodontal lesions.

Over the last decades, scanning electron microscopy (SEM) proved to be invaluable for ultrastructural investigation, allowing imaging of the overall appearance and/or specific features of oral biofilms, e.g., microbial colonies and individual cells, glycocalyx, the presence of inorganic products. The aim of this study was the observation and evaluation of the morphology of the biofilm of endodontic-periodontal lesions (EPL) with a modified protocol involving a simplified histologic sample preparation and a low-vacuum SEM examination method. Twenty-one teeth with endodontic-periodontal involvement, extracted for periodontal reasons, were carefully washed with saline, underwent fixation in modified Karnovsky solution and were dehydrated in alcohol series. Samples were examined under low-vacuum SEM. Radicular surfaces were evaluated qualitatively and semiquantitatively for several characteristics, including the presence of bacterial types, the biofilm morphology and the content of root resorptions. Radicular surfaces were divided in four conventional zones Surfaces were evaluated for several characteristics: Presence of bacterial types, biofilm morphology, presence of root resorptions. High-quality images, relevant for endodontic-periodontal biofilms were collected. Continuous, established biofilm was found on all examined surfaces, its detection varying from 19% of the samples on the wall of cemental cone to 52.3% on the radicular surface of the periodontal pocket. Observed microorganisms included cocci, rods an filaments. Spirils and motile bacteria were only accidentally found. SEM investigation of surfaces involved in EPL revealed less surfaces covered by mature biofilm (in only 28.5% of the samples in the ‘transition zone’), especially rods and filaments associated with cemental resorptions and calculus. Biofilm elements were better represented in periodontal pockets than in other zones of EPL (detected in up to 81% of the samples). A strong correlation between mature biofilm and the presence of cocci appears on all investigated zones (P<0.01). Microbiota appeared to be morphologically similar in apical and periodontal areas, especially in old EPL.

Nano-zerovalent manganese/biochar composite for the adsorptive and oxidative removal of Congo-red dye from aqueous solutions

Congo-red (CR), a precursor of textile products and a contaminant of great concern, has contaminated aquatic environments. Here, we explored the synthesis of mesoporous nano-zerovalent manganese (nZVMn) and Phoenix dactylifera leaves biochar (PBC) composite for the removal of CR from water. The nZVMn/PBC adsorbed 117.647 mg/g of CR versus 25.316 mg/g by PBC at [CR]0 = 20 mg/L and [PBC]0 = [nZVMn/PBC]0 = 500 mg/L. Variation of [nZVMn/PBC]0, [CR]0 and pH influenced the adsorption of CR. Freundlich adsorption isotherm and pseudo-first-order kinetic models best fitted CR adsorption. The H2O2 coupling with nZVMn/PBC promoted removal of CR possibly due to the formation of hydroxyl radical (●OH) and caused 95 % removal of CR versus 77 % by nZVMn/PBC alone. The ●OH scavengers inhibited the removal of CR. The nZVMn/PBC showed a good reusability and efficient removal of CR up to the seventh cycle of treatment. Results reveal that nZVMn improved performance, thermal stability and reusability of biochar. Degradation products from ●OH-mediated degradation of CR were studied by ultraperformance liquid chromatography with mass spectrometric detector to establish degradation pathways. The ion-chromatographic analysis showed the formation of non-toxic inorganic acetate product, which suggests high potential of the newly fabricated adsorbent in the removal of CR.

Avoiding Rice-Based Cadmium and Inorganic Arsenic in Infant Diets Through Selection of Products Low in Concentration of These Contaminants

Cadmium in the diet is of concern as it is a renal toxicant and a carcinogen, with a half-life in the body measured in decades. Inorganic arsenic is a chronic carcinogen. For many subpopulations, rice and rice products may be the dominate source of cadmium and inorganic arsenic. In particular, rice porridge, cereal and cake are widely used to feed infants (children < 4.5 years old). In the EU standards for cadmium infant foods in general has been set at 40 μg/kg w.wt., and for inorganic arsenic in rice-based infant foods the standard is 100 μg/kg w.wt.. Here we report cadmium and inorganic arsenic concentrations in rice products marketed for infants, and rice containing products that infants may eat but that are not specifically designated for infants. It was found that while rice-based infant foods conformed to the standards, their non-infant food (generic) analogues did not. Non-infant rice crackers and puffed rice cereals, in particular, had concentrations above these standards for both cadmium and inorganic arsenic. Polished pure rice grain purchased in the UK, but sourced from different countries, was also problematic. Basmati, Italian, Spanish and Thai rice, either exceeded one or the other of the cadmium and inorganic arsenic safety thresholds for infants, or both. Egyptian rice grain was particularly low for both toxins. Therefore, if those responsible for infants want to lower exposure to cadmium and inorganic arsenic, they should stick to foods specifically labeled for infants, or carefully source low cadmium and inorganic arsenic rice-based products that are not specifically labeled as being for infant consumption, or minimize exposure to rice-based foods.

Recent advances of polymer carbon nitrides toward photosynthesis of hydrogen peroxide

Hydrogen peroxide (H2O2) is a kind of basic inorganic chemical product, which has been extensively developed in biology, chemistry, pharmacy, and environmental protection. H2O2 is mainly produced by the energy-wasting and environmentally-harmful anthraquinone process in industry. Photocatalyic synthesis of H2O2 by utilizing solar energy, water and O2 can reduce the production cost and the environment pollution, therefore has brought a hot-spot of research. In this review, we summarize the recent research advances in synthesizing and modificating polymer carbon nitride-based photocatalysts, and their applications in the photosynthesis of H2O2. The current challenges and opportunities of the polymer carbon nitride-based photocatalysts for the photosynthesis of H2O2 are also discussed.

A particle tracking velocimetry method to measure size and charge distributions in tribocharged powder particles

Simultaneous charge and size of tribocharged particles suspended in a gas stream are measured using image analysis. Under the action of a homogeneous electric field, drag, and electric forces are the main factors influencing particle trajectory, from which electric charge and polarity are derived. We could check that the system operates in a laminar gas regime inside the analysis cell since high flow turbulences would alter the particle “electrical” path, thus invalidating the measurement. Single component granular materials and binary mixtures are studied, all cases showing bipolar distributions and dependence on particle size. Mixture composition affects the overall charge polarity in the dispersed powder, and this effect can not solely be attributed to the weight proportion of the components. PTV is a powerful tool in techniques used for triboelectric dry separation of organic and inorganic products since their efficiency relies much on the charge to mass ratio.

Synthesis of highly active biocompatible ZrO2 nanorods using a bioextract

The use of organic–inorganic metal oxide products in biomedical applications has emerged as the most expanding field. To have long-lasting stability and improved reliability, a biomaterial must be specially chosen and have bioactivity and mechanical properties from the application's point of view. Rambutan (Nephelium lappaceum L.) fruit is considered as one of the bioactive components. In this study, ZrO2 is prepared by hydrothermal route using a green rambutan extract as a reducing agent and it used for biomedical applications. It was found that ZrO2 nanorods hamper the growth of cancerous cells in a dose-dependent manner at a half-maximum inhibitory concentration of 55.32 μg mL−1. Phase-contrast microscopic studies confirm that ZrO2 nanorods disrupt the cell membrane and induce cell death. Keeping this in mind, ZrO2 nanorods can be a promising agent in biomedical applications.

Mechanistic study of visible light-driven CdS or g-C3N4-catalyzed C[sbnd]H direct trifluoromethylation of (hetero)arenes using CF3SO2Na as the trifluoromethyl source

The mild and sustainable methods for CH direct trifluoromethylation of (hetero)arenes without any base or strong oxidants are in extremely high demand. Here, we report that the photo-generated electron-hole pairs of classical semiconductors (CdS or g-C3N4) under visible light excitation are effective to drive CH trifluoromethylation of (hetero)arenes with stable and inexpensive CF3SO2Na as the trifluoromethyl (TFM) source via radical pathway. Either CdS or g-C3N4 propagated reaction can efficiently transform CF3SO2Na to CF3 radical and further afford the desired benzotrifluoride derivatives in moderate to good yields. After visible light initiated photocatalytic process, the key elements (such as F, S and C) derived from the starting TFM source of CF3SO2Na exhibited differential chemical forms as compared to those in other oxidative reactions. The photogenerated electron was trapped by chemisorbed O2 on photocatalysts to form superoxide radical anion (O2−) which will further attack CF3 radical with the generation of inorganic product F− and CO2. This resulted in a low utilization efficiency of CF3 (<50%). When nitro aromatic compounds and CF3SO2Na served as the starting materials in inert atmosphere, the photoexcited electrons can be directed to reduce the nitro group to amino group rather than being trapped by O2. Meanwhile, the photogenerated holes oxidize SO2CF3− into CF3. Both the photogenerated electrons and holes were engaged in reductive and oxidative paths, respectively. The desired product, trifluoromethylated aniline, was obtained successfully via one-pot free-radical synthesis.

Solids management in freshwater-recirculating aquaculture systems: Effectivity of inorganic and organic coagulants and the impact of operating parameters

Coagulants are widely used for solids (uneaten food, faeces, etc.) management in recirculating aquaculture systems (RAS), but no recent research has been performed on the effectiveness of different coagulants in treatment of aquaculture sludge. This study examined the effectivity of selected inorganic (polyaluminium chloride, PAC) and organic products (polyamine- and starch-based) as coagulant agents for solids management in RAS. Reductions in residual concentrations of total phosphorus (tot-P), phosphate‑phosphorus (PO4-P), suspended solids (SS) total nitrogen (tot-N), nitrate‑nitrogen (NO3-N), ammonium‑nitrogen (NH4-N), aluminium (Al) and chemical oxygen demand (COD) in reject water were determined. The effect of process parameters (coagulant type, dose, mixing and sedimentation time) on sludge treatment was also evaluated. The PAC products tested were most effective at concentrating pollutants (Tot-P, PO4-P, SS, COD) in RAS sludge into the solid phase. The organic products tested, especially a high-molecular-weight polyamine product (pAmine1), achieved good performance and can be considered a valid alternative to inorganic salts. At optimum dose, PAC (dose 32 mg/L) and pAmine1 (dose 15 mg/L) removed, respectively, 99.4% and 82.8% of turbidity, 98.2% and 65.4% of PO4-P and 97.7% and 73.6% of SS. The mixing time applied in flocculation and the time allowed for sedimentation had significant effects on coagulant performance, with the organic coagulants being most affected. Flocculation times of 5–15 min and sedimentation times of 15–60 min showed good results and can be used as a starting point in process optimisation with both inorganic and organic coagulants. The use of coagulants for treatment of RAS sludge enhances flock formation and improves particle settling characteristics, substantially decreasing nutrient, organics and solids concentration in reject water.

Characteristics and Sources of Inorganic Ions and Organic Acids in Precipitation in the Northern Suburb of Nanjing, China

Rainwater samples were collected in Nanjing from December 2016 to November 2017. Water-soluble ion and organic acid content in rainwater samples was determined to analyze the chemical characteristics of precipitation and their seasonality. The positive matrix factorization (PMF) model was employed to identify the potential sources of precipitation. The results show that the volume-weighted mean of pH in precipitation was 5.6, which was higher than the results of previous studies conducted in Nanjing. The volume-weighted mean of total ions was 297.3 μmol·L-1, and the concentrations of each species were in the order of NH4+ > Ca2+ > K+ > Na+ > Mg2+ for cations and NO3- > SO42- > Cl- > F- for anions. The volume-weighted mean of organic acids was 2.86 μmol·L-1, with organic acids accounting for 2.2% of the total anions. CHO2-, C2H3O2-, and C2O42- were the main organic acids in precipitation with annual volume-weighted means of 1.35, 1.05, and 0.26 μmol·L-1, respectively. A significant seasonality was observed for the ions and organic acids. The volume-weighted mean of inorganic ions was higher in winter and spring compared to those in summer and autumn. On the other hand, the volume-weighted mean of total organic acids was the highest in summer, followed by spring, and the lowest in winter. High concentrations of organic acids in the summer can be attributed to the biogenic emissions from plants. The ratio of formic and acetic (F/A) showed that organic acids mainly originated from primary emissions (e.g., biogenic emissions, combustion of organics, and traffic emissions) rather than atmospheric oxidation processes. Using the PMF model, we found that marine sources and secondary inorganic products (40.0%) were the predominant sources of inorganic ions and organic acids in precipitation, followed by burning of biomass (22.2%), continental origin and waste incineration (22.0%), secondary organic products (14.5%), and biological emissions along with their secondary products (1.3%).

Modification of a Ceramic Brick Additives of Inorganic Technogenic Products of Water Treatment of Combined Heat and Power Plant

Waste of combined heat and power plants represents a certain danger to the environment, and hence the economic problems. However such waste contains substances that are advisable to use for production of construction and finishing materials. Technogenic products of water treatment from the Yuzhnaya combined heat and power plant (sludges of chemical water treatment – code 8410500) are a calcite mixture containing more than 64 wt. % calcite. The mineralogical composition of inorganic waste has been determined while using X-ray and IR-spectral researches. Mechanical activation of calcite inorganic wastes leads to grinding of calcite and a decrease in the amount of adsorbed water, which affects the increase in the content of silica frame structures, the reactivity of which directly depends on their quantity. Changes in the structure of silicon dioxide during mechanical activation are established according to IR studies. The results of X-ray and IR studies of the Zapolie deposit clay used in ceramic brick production technology make it possible to attribute it to raw materials with high reactivity. An experimental batch of ceramic bricks has been produced at JSC “Obolsky Ceramic Plant” with addition of calcite inorganic waste from combined heat and power plants. An X-ray diffraction analysis of samples of the obtained bricks having standard composition and with addition of waste has been carried out. The influence of calcite inorganic waste content in the feedstock on the process of ceramic brick structure formation has been stu-died in the paper. Addition of chemical water treatment waste containing calcium carbonate up to 15 wt. % to the Zapolye clay mixture helps to reduce a firing temperature and an appearance of the melt. This leads to crystallization processes of solid minerals from the melt and an increase in the amount of glass phase which contributes to improvement of strength properties in ceramic bricks. The possibility of using inorganic waste (sludges of chemical water treatment – code 8410500) of combined heat and power plants as a component of emaciated additives in clay raw materials in the process of ceramic brick production has been established in the paper.

A novel core-shell structured α-Fe2O3/Cu/g-C3N4 nanocomposite for continuous photocatalytic removal of air ethylbenzene under visible light irradiation

In this study, a novel α-Fe2O3/Cu/g-C3N4 nanocomposite was prepared via a simple and facile procedure. A continuous flow reactor of gaseous ethylbenzene was used to assess the photocatalytic performance of the synthesized catalysts. The results of XRD, FT-IR, SEM-EDS, and elemental mapping indicated that the g-C3N4 shells were successfully coated on the surface of Cu-deposited α-Fe2O3 nanospheres. Compared to the pure g-C3N4 and α-Fe2O3, and as well as α-Fe2O3/g-C3N4, a higher specific surface area, lower recombination of charge carriers, and also a well visible light absorption were observed for α-Fe2O3/Cu/g-C3N4 nanocomposite, by using N2 adsorption-desorption, PL, DRS techniques. Accordingly, this composite provided a remarkably increased photocatalytic performance and stability for the removal of air ethylbenzene, through an efficient Z-scheme mechanism. These improvements can be originated from a well-designed core-shell structure. Moreover, no organic byproducts were found at the outlet of the reactor and carbon dioxide was the only inorganic product of ethylbenzene photocatalytic degradation. This work showed that the α-Fe2O3/Cu/g-C3N4 nanocomposite is promising in the removal of air ethylbenzene.

Rapid degradation of dichloroacetonitrile by hydrated electron (eaq–) produced in vacuum ultraviolet photolysis

Dichloroacetonitrile (DCAN) is one of the most toxic and common nitrogenous disinfection by-products in water treatment. It is necessary to understand how this compound can be removed. In this study, the effectiveness of vacuum ultraviolet (VUV) at 185 nm was evaluated to destroy DCAN. When water is exposed to VUV, hydroxyl radicals (HO•), hydrogen atoms (H•), and hydrated electrons (eaq−) are generated. The individual contributions of these reactive species to DCAN degradation were distinguished using multiple scavengers. The results showed that eaq– was the most important species for DCAN degradation. The second-order rate constant for eaq– reacting with DCAN was calculated to be 3.16 × 1010 M−1s−1 using a quantitative structure-activity relationship (QSAR) method adopted from previous study, and determined to be 3.76 (±0.02) × 1010 M−1s−1 by competition kinetics. Although dissolved oxygen (DO) at 8 mg/L consumed 86% eaq−, the rest of eaq− still led to 93% removal of DCAN within 20 min. Chloride was the major inorganic product of DCAN degradation, while nitrate and nitrite were minor products. Quantum chemical calculation and mass balance calculation under an oxygen free condition further suggested that cleavage of C–Cl bonds was the major pathway by eaq– attack. This study demonstrated the significant role of eaq– in micropollutant destruction during VUV treatment.

The Prospects of the in situ and ex situ Use of Aqueous Solutions of Hydrogen Peroxide Electrogenerated from Oxygen

The results and prospects of the in situ (in the cell volume) and ex situ (outside the cell) use of aqueous solutions of hydrogen peroxide electrogenerated from oxygen in gas-diffusion electrodes (GDE) of carbon black are discussed. It is shown that using GDE based on technological A-437E carbon (acetylene black) and mesostructured carbon CMK-3 allows the Н2О2 solution with the concentration higher than 3 M to be obtained. It is found that electrosynthesized hydrogen peroxide may be used in situ with the high efficiency both in the indirect electrosynthesis of important organic and inorganic target products and in the destruction of organic and inorganic pollutants present in waste waters of different origin. Under the ex situ conditions, it is possible to synthesize the more concentrated solutions of Н2О2, organic peroxoacids, and inorganic peroxosolvates and also to carry out mineralization of exometabolites in autonomous life-support systems. These results may be helpful in selecting the most appropriate versions of using hydrogen peroxide solutions electrogenerated from oxygen for solving particular problems.

Aplicação da ferramenta de Análise de Ciclo de Vida (ACV) no processo de tratamento de efluentes em uma lavanderia de beneficiamento de jeans

A temática de sustentabilidade na indústria têxtil ganha cada vez mais força, através da adoção de práticas e ferramentas de gestão ambiental como a Análise de Ciclo de Vida (ACV) que permitam minimizar os impactos ambientais negativos e otimizar processos produtivos em busca de estratégias sustentáveis. O presente estudo teve como objetivo a aplicação da ferramenta de ACV na Estação de Tratamento de Efluentes (ETE) em uma Lavanderia de Beneficiamento de Jeans (LBJ) e comparar os danos ambientais e sociais relacionadas ao tratamento do Efluente Industrial (EI) gerado após o beneficiamento das peças. Foi verificado que o uso de produtos químicos inorgânicos, apresentam os principais poluentes nas categorias do estudo, com impactos acima de 90%. A energia elétrica apresentou impactos significativos, o que sugere a adoção de alternativas como a dosagem manual ou redução do tempo de funcionamento dos equipamentos.

Analysis of women farmers’ involvement in organic farming of maize in Ohaji-Egbema Local Government Area of Imo State

The study analysed women farmers’ involvement in organic farming of maize in Ohaji-egbema, local government area of Imo state, Nigeria. It specifically described the socio-economic characteristics of women organic maize farmers, identified the organic practices engaged by women maize farmers, ascertained women farmers’ level of involvement in organic farming of maize and identified the constraints militating against organic production of maize among farmers in the study area. Data for the study were collected from 80 women organic farmers through a multistage sampling procedure using structured questionnaire. Descriptive statistics and regression analysis were used for the analysis of the data generated. Results revealed that the majority (98.75%) had formal education with a mean age of 55 years. Investigation on the organic practices showed that women in organic maize farming practiced more of intercropping (98.8%), shifting cultivation (85%) as well as animal manure (54%). Result on the level of involvement showed that 52.5% of the farmers were moderately (6-10 organic practices) involved in organic farming. Lack of certification and distinction between organic and inorganic products in the market (82.5%) were the major constraints. farming experience, income, educational level and household size were significant and positively related to women involvement in organic farming at 5% level of significance. It was concluded that women are moderately involved in organic farming of maize in the study area. The study therefore recommends that there should be promotion for distinction of organic products in the market. Also the study recommends that the federal Government should enact a policy that will promote organic farming and their certification.&#x0D; Key words: Organic farming, maize farmers, involvement.

Acute toxicity profile and Sun Protection Factor (SPF) nanoemulgel combination of C-phenylcalix[4]resorcinaryl octacinnamate, C-methylcalix[4]resorcinaryl octabenzoate, and quercetin in vitro and in vivo

Background: The ageing process (photoaging) can be caused by sun exposure, especially ultraviolet light. Organic and inorganic sunscreen products are commercially available. Two calixarene organic compounds, namely C-phenylcalix[4]resorcinaryl octacinnamate and C-methylcalix[4]resorcinaryl octabenzoate, have been successfully synthesized. Besides, the antioxidant quercetin can be potentially combined with these two compounds since ultraviolet rays also cause reactive oxygen species. This study aimed to evaluate the acute toxicity profile in vitro by cell line Vero and to develop the optimal activity of the product in New Zealand rabbit skin.Methods: Optimal formulation of three formulas nanoemulgel of sunscreen was using  D Optimal Mixture Design. Acute cytotoxicity test in vitro by culture cell line Vero was using randomized post-test only control group design. The activity of the product was measured by the value of Sun Protection Factor (SPF) in vivo using randomized post-test only control group design. Data of acute toxicity in vitro test (IC50 value) was analyzed using probit analysis and activity sun protection factor was analyzed using one-way ANOVA on SPSS version 20 for Windows. Results: The in-vitro toxicity test of formula 1, 2, 3 nanoemulgel were 2,940.569 µg/mL, 13,489.728 µg/mL, and 6,289.248 µg/mL respectively. The formula 1 nanoemulgel sunscreen products were produced with the three highest SPF values. SPF in vivo test showed that the nanoemulgel protection capability of the formula 1 with three different doses were 34; 36; dan 43 respectively. Conclusion: It can be concluded that the nanoemulgel sunscreen products were successfully formulated with high in vivo SPF value and can be potentially developed as organic sunscreens in the future because it is not toxic in culture cell.

Thermo-oxidative Reactivation of Active Coal Used in Streptomycin Production

The spent active coal of streptomycin production contains on its surface the remains of inorganic acids, organic-originated alcohols and waste products, spores, mycelium of Streptomyces griseus, which after entering the environment with wastewater cause a significant harm to it. The recycling of that coal and its reuse betters the economics of production and prevents harmful impurities from entering the environment together with that coal. Here it is demonstrated that thermal heating up to 300 °C allows to increase the adsorption activity according to methylene blue test and pH of aqueous extract of recycled sorbents close to the regulatory values, which raises the possibility of their re-use in the production of streptomycin. The raise of temperature more than 300 °C leads to decomposition of high-molecular organic substances on the surface of a coal with subsequent formation of a carbon film which covers the adsorbing pores and worsens the adsorption properties of active coal. After treatment with water vapor at a temperature of 800 °C the characteristics of the active coal meet the regulatory requirements of streptomycin production. Rational way to dispose an active coal which lost its recyclability is a burning at temperatures more than 800 °C. This completely neutralizes all the harmful impurities.

Graphene oxide enhanced ozonation of 5-chloro-2-methyl-4-isothiazolin-3-one: Kinetics, degradation pathway, and toxicity

Kathon is among the most common non-oxidative biocides, containing 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT) and methylisothiazolone (MIT) as the active ingredients. In our previous work, MIT was shown to be efficiently removed by ozonation. In this work, we found that ozonation didn’t readily degrade CMIT. Rate constants kO3, CMIT and k·OH, CMIT, determined to be 6.43 L mol−1 s−1 and 7.8 × 109 L mol−1 s−1, indicated that hydroxyl radicals played a more important role than ozone molecule in the CMIT ozonation which was also proved by the significant inhibition (55.7 %) when adding t-butanol (TBA). Graphene oxide (GO) greatly enhanced the CMIT ozonation, and degradation efficiency raised from 15 % to 100 % after 10 min through the increased production of hydroxyl radical. Basic conditions benefited the CMIT degradation compared with acidic and neutral conditions by promoting ozone decomposition and hydroxyl radical generation, while high carbonate and humic acid concentrations had slight influence on the CMIT degradation. In spite of the complex water matrix, CMIT degradation by GO enhanced ozonation was applicable in reverse osmosis concentrate (ROC). Based on the identification of the inorganic and organic products, a possible CMIT degradation pathway was proposed. However, CMIT transformation products still showed toxicity to Photobacterium phosphoreum and Daphnia magna even after a longer ozonation time.

Fabrication of highly isotropic porous alumina refractory clinkers consisting of platelets using a gelatin-sol

ABSTRACT Porous alumina bodies are expected to find application as refractory materials to reduce energy consumption during the manufacture of inorganic products. The porosity of such bodies can be efficiently increased by using alumina platelets to form a so-called “house-of-cards” structure. This technique was employed in the present study, together with a gelatin-sol (as binder) and freeze-drying. The porosity, compressive strength, and thermal conductivity of a porous alumina body made in this manner and heat-treated at 1600°C were 80.2%, 1.7 MPa, and 0.94 W/m−1∙K−1, respectively. These physicochemical properties would allow this alumina to be used as a thermal insulation refractory clinker material.