Co-pyrolysis of oil sludge with hydrogen-rich plastics in a vertical stirring reactor: Kinetic analysis,emissions, and products

● Collaborative treatment of plastics and OS was established to improve oil quality. ● PE addition successfully improved OS pyrolysis process by deploying H/C_eff ratio. ● Higher H/C_eff ratio promoted cracking to obtain more gas and light oil fractions. ● The degradation of PE and OS was promoted each other under their temperature range. Pyrolysis is an effective method to treat oily sludge (OS) due to its balance between oil recovery and nonhazardous disposal. However, tank bottom OS contains a high content of heavy fractions, which creates obstacles for pyrolysis due to the high activation energy. The incomplete cracking of macromolecules and secondary polymerization decreases the oil quality and causes coking during the operation process. This study introduced polyethylene (PE) into OS to deploy the H/C_eff ratio of feedstocks for pyrolysis. A strong interaction between OS and PE during copyrolysis could be observed from the TG/DTG curves. PE tightly participated in OS degradation, while OS also promoted PE degradation at high temperature. Apparent pits were generated in solid residues from copyrolysis, which was attributed to the uniform and violent gas release. In addition to HCN, other nitrogenous and sulphurous pollutants were inhibited. Accordingly, more gas products were attained after PE addition with more value-added compositions of alkanes and alkenes. Although the oil yield decreased after PE addition, the oil products from copyrolysis possessed higher heating values and higher contents of light fractions with short chains as well as paraffins. Consequently, copyrolysis of OS and PE significantly improved the pyrolysis process and resulted in high oil quality.     

CdS and Ag synergistically improved the performance of g-C3N4 on visible-light photocatalytic degradation of pollution

Environmental Science and Pollution Research - CdS-AgO@g-C3N4 nanocomposites were successfully synthesized and characterized by XRD, N2 physical adsorption, XPS, SEM, TEM, EDX, and UV–Vis DRS...     

Preparation and evaluation of humic acid–based composite dust suppressant for coal storage and transportation

Environmental Science and Pollution Research - To mitigate environmental pollution caused by the escape of dust during coal storage and transportation, humic acid (HA) and grafted acrylamide (AM)...     

An improved method used for evaluating potential environmental pollution risk based on spatial distribution and density of farms

Environmental Science and Pollution Research - The livestock manure nitrogen load on farmland (LMNLF) is often used to assess the potential environmental pollution risk of livestock manure nitrogen...     

Leaching behavior of heavy metals from municipal solid waste incineration bottom ash and its geochemical modeling

With the increase in the number of municipal solid waste incineration (MSWI) plants constructed in China recently, great attention has been paid to the heavy metal leaching toxicity of MSWI residues. In this study, the effects of various parameters, including extractant, leaching time, liquid-to-solid ratio, leachate pH, and heavy metal content, on the release properties of Cd, Cr, Cu, Ni, Pb, and Zn from MSWI bottom ash were investigated. Partial least-squares analysis was employed to highlight the interrelationships between the factors and response variables. Both experimental research and geochemical modeling using Visual MINTEQ software were conducted to study the pH-dependent leaching behavior of these metals in fresh and weathered bottom ash, considering precipitation/dissolution and surface complexation reactions (adsorption by hydrous ferric oxide and amorphous aluminum oxide/hydroxide). The results showed that leachate pH was the predominant factor influencing heavy metal leachability. The leaching of Cu, Pb, and Zn was mainly controlled by precipitation/dissolution reactions, whereas surface complexation had some effect on the leaching of Cr, Cd, and Ni for certain pH ranges. The modeling results aggreed well with the experimental results. Part of this work was presented at the Fourth International Conference on Combustion, Incineration/Pyrolysis and Emission Control (i-CIPEC)     

交际教学法在大学英语教学中的应用

交际法已经发展成为一种世界规模的外语教学理论和教学方法,成为当今世界各国外语教学界普遍承认和接受的基本原则.通过对交际教学法的进一步研究分析,叙述了什么是交际教学法,阐述了运用交际教学法组织大学英语教学的模式和交际教学法在大学英语教学中的运用,指出教师应充分运用交际教学法的基本原理更好地来提高中国英语教学水平.     

高性能纤维在个体防护装备上的应用现状及前景分析

高性能纤维是从化学纤维演化而来，是指耐高温、耐气候、耐化学腐蚀、质量轻、强度高、模量高的特种纤维材料。本文结合几种典型的高性能纤维的具体性能，对高性能纤维在个体防护装备上的应用现状及前景作了分析，旨在进一步推动高性能纤维在个体防护装备上的应用，从而在不同的使用情况下增强个体防护装备对人体的保护功能。     

城市热环境及其微热环境的改善

以苏南５市县３０年来热环境诸因素的变化资料为依据,分析城市区域特征所引起的热环境诸因素的变化趋势,介绍包括规划城市区域的道路网,控制建筑物布局的密度,以及城市绿化和水面等在内的城市规划和建筑设计措施对于改善城市区域微热环境的效用。     

Phytotoxicity and groundwater impacts of leaching from thermal treatment residues in roadways

The use of coal fly ash (CFA), municipal solid waste incinerator bottom ash (MSWIBA) and flue gas desulfurization residue (FGDR) in road construction has become very common owing to its economical advantages. However, these residues may contain toxic constituents that pose an environmental risk if they leach out and flow through the soil, surface water and groundwater. Therefore, it is necessary to assess the ecotoxicity and groundwater impact of these residues before decisions can be made regarding their utilization for road construction. In this study, the physico-chemical characteristics, leaching and phytotoxicity of these residues were investigated. Specifically, multivariate analyses were used to evaluate the contributions of the leaching constituents of the CFA, MSWIBA and FGDR leachates to the germination index of wheat seeds. B, Ba, Cr, Cu, Fe and Pb were found to be more toxic to the wheat seeds than the other heavy metals. Furthermore, the leached concentrations of the constituents from the CFA, MSWIBA and FGDR were below the regulatory threshold limits of the Chinese identification standard for hazardous wastes. Analyses conducted using a numerical groundwater model (WiscLEACH) indicated that the predicted field concentrations of metals from the CFA, MSWIBA and FGDR increased with time up to about 30 years at the point of compliance, then decreased with time and distance. Overall, this study demonstrated that the risks resulting from MSWIBA, CFA and FGDR leaching could be assessed before its utilization for road construction, providing crucial information for the adoption of these alternative materials.     

Insights into sludge granulation during anaerobic treatment of high-strength leachate via a full-scale IC reactor with external circulation system

In this study, a full-scale internal circulation(IC) reactor coupled with an external circulation system was developed to treat high-strength leachate from a municipal solid waste(MSW)incineration plant, in which anaerobic sludge granulation was intensively investigated. Results showed that the IC reactor achieved excellent treatment performance under high organic loading rates(OLR) of 21.06–25.16 kg chemical oxygen demand(COD)/(m3? day). The COD removal efficiency and biogas yield respectively reached 89.4%–93.4% and 0.42–0.50 m3/kg COD.The formation of extracellular polymeric substances(EPS) was closely associated with sludge granulation. Protein was the dominant component in sludge EPS, and its content was remarkably increased from 21.6 to 99.7 mg/g Volatile Suspended Solid(VSS) during the reactor operation. The sludge Zeta potential and hydrophobicity positively correlated with the protein/polysaccharide ratio in EPS, and they were respectively increased from-26.2 m V and 30.35% to-10.6 m V and 78.67%, which was beneficial to microbial aggregation. Three-dimensional fluorescence spectroscopy(3 D-EEM) and Fourier transform infrared spectroscopy(FT-IR)analysis further indicated the importance of protein-like EPS substances in the sludge granulation. Moreover, it was also found that the secondary structures of EPS proteins varied during the reactor operation.