Renewable and efficient removal of arsenic from contaminated water by modified biochars derived from As-enriched plant.

There were limited researches on the scientific disposal of As-enriched plants, and how to reduce the available As content in the processed products and improve the utilization value were the key. In this study, the effect and mechanism of biochar produced by the As-enriched Pteris vittate before and after modification on the removal of As(III) in water were studied. The results indicated that the available As contents of Fe-BC300 and Fe-BC500 were reduced by 78.7 % and 91.9 % compared to original biochars, respectively. Modified biochars not only had a large adsorption capacity for As(III) (50.3 and 39.7 mg/g), but also can efficiently oxidize As(III) to As(V). The removal rate of As(III) by modified biochar was still higher than 50% after 3 cycles. The increase of the point of zero charge and the introduction of Fe were the main reasons for its efficient adsorption and oxidation of As(III).

Performance and mechanism of Pb2+ and Cd2+ ions' adsorption via modified antibiotic residue-based hydrochar.

This study investigated the hydrochar-based porous carbon prepared by combining the technical route of hydrothermal carbonization (HTC) + chemical activation. The hydrochar morphology was adjusted by changing the activation reaction conditions and adding metal salts. Experiments showed that the activation of KHCO3 significantly increased the specific surface area and pore size of the hydrochar. Besides, oxygen-rich groups on the surface of the activated hydrochar interacted with heavy metal ions to achieve efficient adsorption. The activated hydrothermal carbon adsorption capacity for Pb2+ and Cd2+ ions reached 289 and 186 mg/g, respectively. The adsorption mechanism study indicated that the adsorption of Pb2+ and Cd2+ was related to electrostatic attraction, ion exchange, and complexation reactions. The "HTC + chemical activation" technology was environmentally friendly and effectively implemented antibiotic residues. Carbon materials with high adsorption capacity can be prepared so that biomass resources can be utilized with excessive value, as a consequence presenting technical assistance for the comprehensive disposal of organic waste in the pharmaceutical industry and establishing a green and clean production system.

Co-disposal and reutilization of municipal solid waste and its hazardous incineration fly ash.

Compared to landfill, MSW incineration (MSWI) not only eliminates its innate secondary pollution and land occupation, but also yields a net emission reduction. Regretfully, MSWI produces hazardous incineration fly ash (IFA) enriched with potentially toxic elements and dioxins. Given these, a harmless integrated scenario of co-disposal and resource reutilization of MSW and its hazardous IFA is proposed and subjected to technical and economic analysis. It introduces an IFA melting furnace, as an onsite modular integration, which serves as a bridge between the MSW incinerator and the commercial rock wool production line. The incinerator burns MSW for heating and electricity supply. The melting furnace further burns out the highly toxic dioxins adsorbed on IFA, as well as solidifying the potentially toxic elements into the molten slag, which substitutes for basalt as raw materials used for high value-added rock wool production. That achieves collaborative reduction, stabilization, harmlessness and resource reutilization of MSW as an energy source, and its IFA as energy-saving materials, as well as a net carbon emission reduction and high economicbenefits. Even more exciting, as opposed to the serious losses of the other existing scenarios, it is profitable even without the feed-in tariff and fiscal subsidy, both that are the dominating income source of other scenarios including conventional MSWI & IFA landfill and demonstration MSWI with IFA melting & landfill. Discounted Cash Flow technique shows that the profit is âˆ¼ 9.2 RMB per ton of MSW, and it increases with insulation price, feed-in tariff, and fiscal subsidy. With the feed-in tariff and fiscal subsidy, the existing two scenarios and the proposed harmless integrated scenario can produce revenue of 103.8, 98.1-110.5, and 145.0 RMB per ton of MSW, respectively. Nonetheless, several challenges are posed for future industrial applications, such as liquid slag discharge, unstable combustion and possible environmental issues.

Comprehensive Application Technology of Bauxite Residue Treatment in the Ecological Environment: A Review.

The emission of bauxite residue continues to grow with the increase of alumina production capacity, along with the large amounts of bauxite residue currently stored in stockpiles. The exposed problems of high yield, strong alkalinity, low comprehensive utilization rate, and threats to the ecological environment are becoming increasingly prominent. With the strict requirements of environmental protection, improving the comprehensive utilization rate of bauxite residue and bulk consumption of bauxite residue has become an urgent issue to be solved. A large number of researchers have conducted in-depth investigations into the application of bauxite residue over a wide range, and this paper summarizes its application in the environment in recent years, providing guidance for the high value and harmless application of bauxite residue, which can help reduce environmental pollution and human life and health hazards caused by bauxite residue.

CONTENIDO DE POLIFENOLES, CAPACIDAD ANTIOXIDANTE Y TOXICIDAD DE Solanum ferrugineum (SOLANACEAE) CON POTENCIAL MEDICINAL / Polyphenol content, antioxidant capacity and toxicity of Solanum ferrugineum (Solanaceae) with medicinal potential

RESUMEN Solanum ferruginium es una planta que crece en lugares perturbados como maleza, es de uso medicinal poco utilizada que presenta un gran potencial como fuente de antioxidantes debido a su alto contenido en polifenoles. Debido a esto se analizó el contenido de polifenoles, flavonoides, proantocianidinas y capacidad antioxidante in vitro (ensayo de captación de radicales DPPH) en hojas, tallos y planta completa de tres localidades (Las agujas, Parque el Nabo y Bosque la Primavera) de Zapopan, Jalisco, así como su toxicidad subcronica en hojas. En general se observó diferencia significativa (p≤ 0,05), en las muestras de las tres localidades, las hojas presentaron el mayor contenido de polifenoles (15,3±0,7 a 22±0,4 mg expresado como equivalente de ácido gálico (EAG/g) en muestras de Parque el Nabo, flavonoides (7,8±0,3 a 13,3±0,3 mg EC/g) y proantocianidinas (3,4±0,1 a 4,2±0,05 mg expresado como equivalente de catequina (EC/g) en el Bosque la Primavera. La capacidad antioxidante fue similar en todas las muestras, con valores de 8,3 a 17 μg/mL de concentración media inhibitora (CI50). En la prueba toxicológica, los ratones no mostraron signos de toxicidad a ninguna dosis por efecto de la administración de la planta en estudio, por lo que la dosis letal media (DL50) es > 15 000 mg/kg de peso corporal. El contenido de polifenoles y actividad antioxidante en S. ferruginium sobre todo en hojas indican un alto potencial con propiedades farmacológicas además de su inocuidad, por lo que es importante realizar estudios de sus compuestos fenólicos individuales, antes de ser utilizada en farmacología.

ABSTRACT Solanum ferrugineum is a plant that grows like a weed. It is a new medicinal plant with great potential as an antioxidant source due to its high polyphenol content. Because of this, polyphenol, flavonoid, proanthocyanidin, and antioxidant capacity in vitro (radical scavenging test by DPPH) were analyzed in leaves, stems, and whole plants from three localities (Las agujas, Nabo Park, and La Primavera Forest) as well as the subchronic toxicity evaluation in leaves. In general, there was a significant difference (p≤ 0.05) in all samples from the three localities. The leaves showed the highest polyphenol content (15.3±0.7 to 22±0.4 mg AGE/g) in samples from the Nabo Park, flavonoid (7.8±0.3 to 13.3±0,3 mg CE/g) and proanthocyanidins (3.4±0.1 to 4.2±0.05 mg CE/g) in La Primavera Forest. Antioxidant capacity was similar across all samples, showing values of 8.3 to 17 μg/mL of IC50. During the toxicology assay, animal specimens showed no signs of toxicity to the doses resulting from the administration of the plant under study so that LD50 > 15 000 mg/kg Bodyweight. The polyphenol content and antioxidant capacity obtained from S. ferruginium leaves, together with its safety, indicate a high pharmacological potential of this plant. Therefore, it is important to carry out studies of its phenolic compounds before being used in pharmacology.