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Alkali dissolution is an effective method to regulate the pore structure of porous mineral material. The main chemical composition of diatomite is amorphous SiO 2 , which can be dissolved in alkali dissolution. The diatomite samples with alkali dissolution treatment were systematacially characterized by the particle size analysis, low temperature nitrogen adsorption, MIP, fractal theory, SEM, TEM, XRD, FTIR and surface hydroxyl density to analyze the pore structure and surface properties. And the humidity control performance of diatomite was tested under different temperatures and relative humidities. The relationship among pore structure, surface properties and humidity control performance were analyzed. The results show that alkali dissolution can regulate the mesoporous and macroporous of diatomite, and some new microporous can generate at high alkali dosage. The specific surface area, mesoporous pore volume, proportion of macroporous volume, surface roughness, heterogeneity of pore structure and number of hydroxyl groups on the surface of diatomite are important factors which determining the humidity control performance. The humidity control performance of diatomite is positively correlated with the specific surface area, mesoporous volume, surface roughness, heterogeneity of pore structure and number of hydroxyl groups on the surface, while is negatively correlated with the proportion of macroporous volume. [ABSTRACT FROM AUTHOR]

Abstract The N-TiO 2 /g-C 3 N 4 @diatomite (NTCD) composite has been prepared through a simple impregnation method, using titanium tetrachloride as precursor and urea as nitrogen-carbon source. Then the effects of calcination temperature on structure, surface property and photocatalytic activity of the catalysts were investigated. And XRD, TEM, XPS, FTIR and UV–vis diffuse adsorption spectroscopy were used to characterize the obtained powders. The photocatalytic activity of the NTCD was evaluated through the reduction of aqueous Cr (VI) under visible light irradiation (λ > 400 nm). The results demonstrated that the nano-TiO 2 particles ranging from 15 to 30 nm in the crystal of anatase are well deposited on the surface of diatomite in the NTCD-500 which calcined at 500 °C for 2 h. Furthermore, the g-C 3 N 4 with the lay thickness of 0.92 nm was attached to the surface of nano-TiO 2. The N-doped TiO 2 and g-C 3 N 4 doped catalysts could co-enhance response in the visible light region and reduce band gap of NTCD-500 (E g = 3.07 eV). And the NTCD-500 sample exhibited nearly 100% removal rate within 5 h for photocatalytic reduction of Cr (VI) which was higher activity than P25, crude TiO 2 @diatomite and g-C 3 N 4 @diatomite. Graphical abstract Image 1 Highlights • The N-TiO 2 /g-C 3 N 4 @diatomite hybrid photocatalyst was prepared and characterized. • The calcination temperature has significant effect on structure and photocatalytic activity of the catalysts. • The N-TiO 2 /g-C 3 N 4 @diatomite heterostructures exhibit superior Cr(Ⅵ) removal rate under visible light irradiation. • The N-TiO 2 and g-C 3 N 4 work together to enhance the photocatalyst reduction of Cr(Ⅵ). The composite exhibit superior Cr(Ⅵ) removal rate and the calcination temperature has significant effect on structure of the catalysts. [ABSTRACT FROM AUTHOR]

This work investigated the size reduction process of calcined black talc using a high energy CJXXM planetary mill. The grinding effects of two different grinding media, aluminia and zirconia, and three kinds of grinding aids, ethanol triethanolamine and sodium hexametaphosphate on the average particle size D50 was compared. The specific surface area, morphology and crystal structure of the ground calcined black talc was characterized by BET, SEM and XRD. The kinetic models of the -1 μm particles in the product are also been studied. The result shows that the zirconia is superior to aluminia as grinding media, and ethanol is a better grinding aid for calcined black talc compared with triethanolamine and sodium hexametaphosphate. The D50 of product can be 1.09 μm within 15 min. No agglomerations between fine particles are formed in the product. The (220) is the most unstable crystal plane . Kinetic models of calcined black talc in a planetary mill under dry superfine grinding conditions using zirconia as grinding media with and without ethanol can be expressed as and respectively. [ABSTRACT FROM AUTHOR]

Using the diatomite as the carrier, the nano-TiO 2 /diatomite composite materials (NTID) were synthesized by the hydrolysis deposition of titanium tetrachloride. Thermodynamic behavior of the as-prepared sample was evaluated by thermo gravimetric (TG) and differential scanning calorimetry (DSC). Structures of the composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The photocatalytic property of the composite was investigated through the degradation of Cu 2+ in aqueous solutions. Effects of various parameters such as initial pH, catalyst amount and initial Cu 2+ concentration on the removal of Cu 2+ were investigated to optimize operational conditions. The results indicate that the nano-TiO 2 immobilized on the surface of carrier was crystallized through calcinations at 700 °C. And the phase of TiO 2 is anatase with the average crystallite size of 13 nm. The removal efficiency of 10 mg/L Cu 2+ solution by the composite reaches 96.63% after irradiation for 3 h under UV-light. [ABSTRACT FROM AUTHOR]

• The development and progression of NAFLD by common pollutants in water is reviewed. • Features in response to each environmental contaminant are elucidated. • The new perspective of joint toxicity of pollutants in water bodies is put forward. The global prevalence of nonalcoholic fatty liver disease (NAFLD) has been increasing rapidly in recent years, which is now estimated to be over 25%. NAFLD is one of the most common chronic liver diseases in the world. At present, with the rapid development of economy and industrialization, many chemicals are released into the environment. These chemical contaminants in the environment might cause harm to human health and result in lipid metabolism disorder during long-term exposure. Moreover, the incentive of many NAFLD cases is unknown, and the environmental risk factors of NAFLD need to be urgently identified. Hence, we focus on the impacts of several popular environmental contaminants in water environment on the development and progression of NAFLD. These contaminants mainly include microcystins (MCs), disinfection by-products (DBPs), heavy metals (HMs), dioxins and polychlorinated biphenyls (PCBs). Through analyzing a great many epidemiological and toxicological studies, we have found positive associations between NAFLD and chronic exposure to these contaminants at the environmental levels. This review may enhance the understanding of liver damage caused by environmental pollutants, which are considered as tangible environmental risk factors for NAFLD. [ABSTRACT FROM AUTHOR]

Highlights: [•] We have prepared three amorphous silica minerals as supports for TiO2 catalysis. [•] We characterized by XRD, SEM, FT-IR, TEM and XPS. [•] We investigated the UV-assisted degradation of Rhodamine B (RhB). [•] TiO2/DE photocatalyst exhibits better catalytic performance at different calcined temperatures. [ABSTRACT FROM AUTHOR]

Based on the urgency of comprehensive utilization of large amount of coal gangue and the demand for the treatment of organic pollution in coal chemical sites and water bodies, novel coal gangue-based persulfate catalytic material (GCM) which can effectively activate peroxymonosulfate (PMS) were prepared by using coal gangue as raw material and adding activator under inert atmosphere. Under the optimized conditions, the degradation rate of GCM-ZnCl 2 material can reach 82.6% in 25min. Among different environmental impact factors, anions have little effect on the degradation rate of phenol, while the initial pH value has a greater impact. When the pH value is 9.0, it belongs to the synergistic effect of alkali activation, and the degradation effect of phenol is relatively better. The GCM-ZnCl 2 material can realize the efficient adsorption of phenol through its large specific surface area and pore volume, and provide more catalytic active sites. The oxygen-containing groups C O (carboxyl, ester, ketone, etc.) on its surface can react with PMS to produce free radical SO 4 •− or induce the production of non-free radical 1O 2 , so as to realize the efficient degradation of phenol. [Display omitted] • Novel coal gangue-based persulfate catalytic materials (GCM) were prepared. • The GCM-ZnCl 2 catalytic material has a large specific area of 141.4 m2/g. • The removal rate of phenol reached 82.6% within 25 min. • Both free radical (.•OH and SO 4 •−) and non-free radical (1O 2) involved in the reaction. • The possible degradation pathways were well analyzed and illustrated. [ABSTRACT FROM AUTHOR]

Abstract: This study presented a novel method for purification of three different grades of diatomite from China by scrubbing technique using sodium hexametaphosphate (SHMP) as dispersant combined with centrifugation. Effects of pH value and dispersant amount on the grade of purified diatomite were studied and the optimum experimental conditions were obtained. The characterizations of original diatomite and derived products after purification were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared spectroscopy (IR) and specific surface area analyzer (BET). The results indicated that the pore size distribution, impurity content and bulk density of purified diatomite were improved significantly. The dispersive effect of pH and SHMP on the separation of diatomite from clay minerals was discussed systematically through zeta potential test. Additionally, a possible purification mechanism was proposed in the light of the obtained experimental results. [Copyright &y& Elsevier]

Over the past decades, inspired by the outstanding properties of clay minerals such as abundance, low-cost, environmental benignity, high stability, and regularly arranged silica-alumina framework, researchers put much efforts on the interface assembly and surface modification of natural minerals with bare photocatalysts, i.e. TiO 2 , g-C 3 N 4 , ZnO, MoS 2 , etc. The clay-based hybrid photocatalysts have resulted in a rich database for their tailor-designed microstructures, characterizations, and environmental-related applications. Therefore, in this study, we took a brief introduction of three representative minerals, i.e. kaolinite, montmorillonite and rectorite, and discussed their basic merits in photocatalysis applications. After that, we summarized the recent advances in construction of stable visible-light driven photocatalysts based on these minerals. The structure-activity relationships between the properties of clay types, pore structure, distribution/dispersion and light absorption, carrier separation efficiency as well as redox performance were illustrated in detail. Such representative information would provide theoretical basis and scientific support for the application of clay based photocatalysts. Finally, we pointed out the major challenges and future directions at the end of this review. Undoubtedly, control and preparation of novel photocatalysts based on clays will continue to witness many breakthroughs in the arena of solar-driven technologies. [Display omitted] • Kaolinite, montmorillonite and rectorite based photocatalysts were well reviewed. • The role of clay in composite photocatalysts was illustrated in detail. • We point out the major challenges and direction of clay based photocatalysts. • This review is meaningful for energy crisis and environmental remediation. [ABSTRACT FROM AUTHOR]

Developing low-cost, high-efficiency catalysts for advanced oxidation processes remain a key issue for the degradation of organic pollutants. In this study, a novel FeCo 2 O 4 /rectorite composite was synthesized via a facile combustion process and employed to activate peroxymonosulfate (PMS) for dealing with atrazine (ATZ). The addition of rectorite could result in higher specific surface area, smaller pore size and more hydroxyl groups, which were beneficial to enrich pollutants to the adsorption sites and provide sufficient reactive sites. After meticulous evaluation, the degradation efficiency of FeCo 2 O 4 /rectorite composite towards ATZ exhibited improved PMS activation efficiency which was about 2.6 times than that of pure FeCo 2 O 4. Based on the characterization results, the sulfate radicals and hydroxyl radicals were considered to be the main free radicals which were involved into the circulation of Co(II)–Co(III)–Co(II) as well as the oxidation of ≡Fe(II), which was responsible for the remarkable catalytic efficiency. In addition, the chemical stability and superior catalytic performance of FeCo 2 O 4 /rectorite should also be attributed to the chemical combination between metal ions and the surface hydroxyl groups of rectorite. Overall, these findings are beneficial for understanding the mechanism of PMS activation by natural mineral-based catalysts and contributing to the practical application of sulfate-based technology for organic wastewater treatment. Image 1 • In situ growth of FeCo 2 O 4 on natural rectorite for PMS activation was achieved. • FeCo 2 O 4 /rectorite composite exhibited higher PMS activation efficiency than pure FeCo 2 O 4. • Hydroxyl groups of rectorite accelerated PMS activation significantly via combining with metal oxide. • Both OH• and SO 4 •− were identified as main reactive species. [ABSTRACT FROM AUTHOR]