Arsenic is an environmental hazard and the reduction of drinking water arsenic levels is under consideration. People are exposed to arsenic not only through drinking water but also through arsenic-contaminated air and food. Here we report the health effects of arsenic exposure from burning high arsenic-containing coal in Guizhou, China. Coal in this region has undergone mineralization and thus produces high concentrations of arsenic. Coal is burned inside the home in open pits for daily cooking and crop drying, producing a high concentration of arsenic in indoor air. Arsenic in the air coats and permeates food being dried producing high concentrations in food; however, arsenic concentrations in the drinking water are in the normal range. The estimated sources of total arsenic exposure in this area are from arsenic-contaminated food (50-80%), air (10-20%), water (1-5%), and direct contact in coal-mining workers (1%). At least 3,000 patients with arsenic poisoning were found in the Southwest Prefecture of Guizhou, and approximately 200,000 people are at risk for such overexposures. Skin lesions are common, including keratosis of the hands and feet, pigmentation on the trunk, skin ulceration, and skin cancers. Toxicities to internal organs, including lung dysfunction, neuropathy, and nephrotoxicity, are clinically evident. The prevalence of hepatomegaly was 20%, and cirrhosis, ascites, and liver cancer are the most serious outcomes of arsenic poisoning. The Chinese government and international organizations are attempting to improve the house conditions and the coal source, and thereby protect human health in this area.

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Efficient utilization of the low-rank coal has been a headachy problem, especially when firing the high alkalicontaining coal in a typical pulverized fuel boiler, where severe slagging and fouling originating from the alkali metal vapors may occur. The additives injection technology has been proved to be a promising method in combating these problems. In this study, the alkali capture mechanism of kaolin was investigated by burning a kind of high-sodium lignite in a laboratory-scale drop tube furnace. The effects of kaolin content, reaction temperature, and particle sizes of both kaolin and fuel on the sodium capture efficiency of kaolin were also investigated. It was found that kaolin could chemically adsorb NaCl, the primary sodium species proved in the flue gas, to form high-melting sodium aluminosilicates such as nepheline and albite, and the nepheline-forming reaction dominated the sorption mechanism. More kaolin addition led to more sodium fixed into the ash. However, the promotion was not that pronounced in high kaolin dosages. The sodium capture efficiency decreased as temperature was increased or larger kaolin particles were injected. Effect of the coal size on the sodium capture efficiency could be neglected in the tested size range. The sodium retention with 6 wt % kaolin addition of the fuel at 1200 °C could attain 70% of the total sodium in the combusted coal, which can considerably reduce the ash-related problems and facilitate the safe firing of high alkali coal in boilers.

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The mechanism of selective catalytic reduction of NOx by propene (C3H6-SCR) over the Cu/Ti0.7Zr0.3O2 catalyst was studied by in situ Fourier transform infrared (FTIR) spectroscopy and density functional theory (DFT) calculations. Especially, the formation and transformation of cyanide (-CN species) during the reaction was discussed. According to FTIR results, the excellent performance of the Cu/Ti0.7Zr0.3O2 catalyst in C3H6-SCR was attributed to the coexistence of two parallel pathways to produce N2 by the isocyanate (-NCO species) and -CN species intermediates. Besides the hydrolysis of the -NCO species, the reaction between the -CN species and nitrates and/or NO2 was also a crucial pathway for the NO reduction. On the basis of the DFT calculations on the energy of possible intermediates and transition states at the B3LYP/6-311 G (d, p) level of theory, the reaction channel of -CN species in the SCR reaction was identified and the role of -CN species as a crucial intermediate to generate N2 was also confirmed from the thermodynamics view. In combination of the FTIR and DFT results, a modified mechanism with two parallel pathways to produce N2 by the reaction of -NCO and -CN species over the Cu/Ti0.7Zr0.3O2 catalyst was proposed.

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Direct propane dehydrogenation (PDH) is an attractive onpurpose strategy for propylene production. Compared with high-priced Platinum and toxic Chromium oxide, ZnO based catalysts attract wide attention due to its low-cost and environment-friendly character. Herein we report silicalite-1 supported ZnO catalysts for PDH reaction. They exhibited an excellent catalytic performance. The catalyst with 5 wt% Zn exhibited the best propane yield with propane conversion reaching 49 % and propylene selectivity around 90 % at a space velocity of 5000 ml • g À 1 • h À 1 . Characterization with N 2 adsorption, XRD, SEM, TEM, EDS, NH 3 -TPD, UV-vis, XPS, 29 Si MAS NMR, FT-IR, Py-IR and TGA reveal that the high activity and stability can be attributed to the dispersed ZnO species due to the interaction between silanol nests of silicalite-1 support and ZnO species.This study may open a promising way for development of highly efficient PDH catalysts.