Study on the removal effect and mechanism of calcined pyrite powder on Cr(VI).

Pyrite exhibits considerable potential as an adsorbent in wastewater treatment. However, few pyrite adsorbents are directly obtained from natural pyrite, as most are composite materials that require a complex preparation process. To develop a pyrite-based adsorbent with a simple preparation process, pyrite was processed by calcination at 400, 600, and 800 °C for 4 h and ball-milled into a fine powder. The adsorption properties of the pyrite powder were systematically explored. The calcined pyrite powder was characterized by SEM-EDS and XRD. The results revealed that the pyrite calcined at 600 °C exhibited excellent adsorption properties and was primarily composed of Fe7S8. The optimum conditions for Cr(VI) removal were a temperature of 45 °C, an adsorbent dosage of 1 g, an equilibration time of 60 min, and an initial pH of 3. Moreover, the calcined pyrite powder exhibited excellent reusability, and the Cr(VI) removal rate exceeded 65% after three cycles. The Cr(VI) adsorption on pyrite can be well described by the Freundlich model and pseudo-second-order kinetic equation. The calcination temperature is the main factor affecting the adsorption performance of pyrite. Therefore, the calcined pyrite powder is expected to be an excellent adsorbent for Cr(VI) in the wastewater treatment industry.

Pyrite has shown promising development prospects in the field of wastewater purification. However, the preparation of most pyrite-based adsorbents is complicated. Upon high-temperature calcination, pyrite is used in traditional Chinese medicine clinics to promote the healing of fractures. The efficiency and underlying mechanism of Cr(VI) adsorption from water using calcined pyrite was investigated. The adsorbent was prepared using a simple method and exhibited excellent adsorption performance, thus allowing its application in preparing ore-based adsorbents for water pollution treatment.

Correlation Between Different Antidiarrheal Treatments and Changes in Chemical Components of Allii Sativi Bulbus Before and After Steaming Treatment Based on Flora Sequencing and In Vitro Experiments.

We investigated the changes in the main active ingredients and pharmacodynamic differences in the therapeutic effect of garlic before and after steaming and the correlation between them. The main active ingredients in raw garlic products (RGPs) and steamed garlic products (SGPs) were determined by high-pressure liquid chromatography and ultraviolet spectroscopy. Acute rapid diarrhea (AD) and antibiotic-induced diarrhea (DD) models were established in rats, and each group was treated with RGP and SGP, respectively. The main chemical components of garlic changed before and after steaming. Garlicin and alliinase were only found in RGP, whereas only alliin was found in SGP. Both RGP and SGP contained garlic polysaccharides. For in vivo experiments on AD, the average rate of loose stools was 100.00 ± 0.00, 31.55 ± 11.76, and 19.14 ± 6.62 in the RGP high-dose and SGP high-dose treatment groups, respectively; in DD, the rates were 91.11 ± 14.40, 19.33 ± 3.63, and 30.56 ± 4.30, respectively (P < .01, treatment vs. model groups). In AD, the average grade of loose stools was 2.33 ± 0.52 and 1.83 ± 0.75 in the model and RGP high-dose treatment groups, respectively (P < .05); in DD, the values were 2.17 ± 0.41 in the model group and 1.67 ± 0.52 in the SGP high-dose treatment group (P < .05). RGP had a better therapeutic effect on AD, mainly related to the antibacterial effect of garlicin in RGP. SGP had a better therapeutic effect on DD, mainly related to the alliin and garlic polysaccharide in SGP. This study could provide evidence to support the clinical use of garlic.

[Impacts on nutrient export by landscape heterogeneity based on sub-watershed].

Landscape features of a watershed are important factors affecting non-point source (NPS) pollution. Sub-watershed bounds were delineated and landscape heterogeneity was analyzed based on GIS and RS in Xitiaoxi watershed which located the upper reach of Taihu Lake area. Nutrient export intensity of sub-watersheds was estimated by revised export coefficient model. Then the relationships between nutrient export and main landscape types, as well as Shannon diversity index (SHDI) in sub-watershed units were analyzed. Results show, TN and TP export intensity have obvious spatial difference, which changed from 3.01 kg/(hm2 x a) to 15.44 kg/(hm2 x a) and 0.049 kg/(hm2 x a) to 0.355 kg/(hm2 x a) respectively. The dominated landscape types including cultivated land and forest land quantitatively related with nutrient export intensity. TN and TP export intensity will decrease 0.203 1 kg/(hm2 x a) and 0.0152 kg/(hm2 x a) respectively with 10% increased of forest area, and will increase 0.5726 kg/(hm2 x a) and 0.0273 kg/(hm2 x a) with 10% increased of cultivated land area. The relationship between nutrient export intensity and SHDI exhibited second-degree polynomial, export intensity increased by SHDI increasing and to maximum when SHDI equals 1.5, then decreased with SHDI increasing. This research results will provide an important reference value for NPS management.