Green Synthesis of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/Cellulose/Polyvinyl Alcohol Hybride Aerogel and Its Application for Dye Removal

A novel Fe₃O₄/cellulose–polyvinyl alcohol (PVA) aerogel was successfully synthesized by an eco-friendly and facile method in this work. Cellulose/PVA matrix was prepared through an environmental friendly physical cross-linking process and further in-situ decorated with Fe₃O₄. Series of Fe₃O₄ decorated aerogels were prepared and the effects of Fe₃O₄ nanoparticles (NPs) on the aerogels were systematic investigated. As-prepared aerogels exhibited desirable properties including nanostructure, relatively high porosity, improved mechanical and superparamagnetism. The TEM results showed that Fe₃O₄ NPs were integrated in the three-dimensional matrix of cellulose/PVA with a diameter of 9–12 nm. Furthermore, the mechanical strength of the aerogels was significantly enhanced after the introduction of Fe₃O₄ NPs. Meanwhile, the obtained Fe₃O₄/cellulose/PVA aerogel exhibited excellent adsorption performance toward methyl blue dye, and can be reused through fenton-like catalysts oxidative degradation of organic dye in H₂O₂ solution. Therefore, they will have a great potential application as eco-friendly and economical adsorbents.     

Antecedents of satisfaction and engagement of low-carbon bicycle-sharing using in China

Transport sector contributed numerous carbon emissions in China. It is important to promote low-carbon bicycle-sharing using in China. This paper aims to analyze the influencing factors of the satisfaction and engagement of bicycle-sharing in China. An extended model of customer satisfaction is established, which considers both customer satisfaction theory and customer engagement theory. We explore the different effect of convenience, health, safety, and facility on satisfaction of bicycle-sharing using. We also explore the role of satisfaction on three different dimensions of engagement: enthusiasm, participation, and social interaction. Multi-group structure equation model is employed to explore the different roles of gender on the determinants of satisfaction and engagement of bicycle-sharing using. The findings reveal that facilities had the larger effect on satisfaction of bicycle-sharing using than safety and health for male. Safety had the largest influence on satisfaction of bicycle-sharing using for female, followed by facility, convenience, and health.

     

Zero-valent manganese nanoparticles coupled with different strong oxidants for thallium removal from wastewater

• Nano zero-valent manganese (nZVMn, Mn⁰) is synthesized via borohydrides reduction. • Mn⁰ combined with persulfate/hypochlorite is effective for Tl removal at pH 6-12. • Mn⁰ can activate persulfate to form hydroxyl and sulfate radicals. • Oxidation-induced precipitation and surface complexation contribute to Tl removal. • Combined Mn⁰-oxidants process is promising in the environmental field. Nano zero-valent manganese (nZVMn, Mn⁰) was prepared through a borohydride reduction method and coupled with different oxidants (persulfate (S₂O₈²⁻), hypochlorite (ClO⁻), or hydrogen peroxide (H₂O₂)) to remove thallium (Tl) from wastewater. The surface of Mn⁰ was readily oxidized to form a core-shell composite (MnO_x@Mn⁰), which consists of Mn⁰ as the inner core and MnO_x (MnO, Mn₂O₃, and Mn₃O₄) as the outer layer. When Mn⁰ was added alone, effective Tl(I) removal was achieved at high pH levels (>12). The Mn⁰-H₂O₂ system was only effective in Tl(I) removal at high pH (>12), while the Mn⁰-S₂O₈²⁻ or Mn⁰-ClO⁻ system had excellent Tl(I) removal (>96%) over a broad pH range (4–12). The Mn⁰-S₂O₈²⁻ oxidation system provided the best resistance to interference from an external organic matrix. The isotherm of Tl(I) removal through the Mn⁰-S₂O₈²⁻ system followed the Freundlich model. The Mn⁰ nanomaterials can activate persulfate to produce sulfate radicals and hydroxyl radicals. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy suggested that oxidation-induced precipitation, surface adsorption, and electrostatic attraction are the main mechanisms for Tl(I) removal resulting from the combination of Mn⁰ and oxidants. Mn⁰ coupled with S₂O₈²⁻/ClO⁻ is a novel and effective technique for Tl(I) removal, and its application in other fields is worthy of further investigation.     

How much heterogeneity? Flow versus area from a big data perspective

Over the past 10 years, there has been an increased recognition that matrix diffusion processes are a significant factor controlling the success of groundwater remediation. New field techniques and modeling tools have, consequently, been developed to understand how contaminants diffuse into and then out of low‐permeability (“low‐k”) zones and assess the resulting impact on groundwater quality. Matrix diffusion, in turn, is driven by one key factor: geologic heterogeneity. The importance of heterogeneity is being emphasized in the groundwater field by general rules of thumb such as “90% of the mass flux occurs in 10%‐20% of the cross‐sectional area” and conceptual models that show most of the groundwater flow occurs through the aquifer's “mobile porosity” which just a small fraction of commonly used effective porosity values (between 0.02 and 0.10 for mobile porosity vs. 0.25 for effective porosity). For this study, 141 boring logs from 43 groundwater remediation sites were evaluated to develop an empirically based estimate of the groundwater flow versus aquifer cross‐sectional area to confirm or reject the general flow versus area rules of thumb. This study indicated that at these 43 sites, an average of 30% of the cross‐sectional area carried 90% of the groundwater flow. Our flow‐only analysis does provide moderate (but not confirmatory) support for the “mobile porosity” concept with an estimated representative mobile porosity value of about 0.11 at the 43 sites.     

Measuring the association of environmental,corporate, financial,and social CSR: evidence from fuzzy TOPSIS nexus in emerging economies

Environmental Science and Pollution Research - The purpose of this research is to measure the combing impact of corporate social responsibility on company performance and to conduct a comparative...     

Toxicity of exogenous antimony to the soil-dwelling springtail Folsomia candida

Environmental Science and Pollution Research - Antimony (Sb) is a toxic pollutant, but data for Sb toxicity to springtails in soil are limited, and the effects of Sb speciation, soil physiochemical...     

Population and community resilience in multitrophic communities

Diversity-stability relationships have long been a topic of controversy in ecology, but one whose importance has been re-highlighted by increasing large-scale threats to global biodiversity. The ability of a community to recover from a perturbation (or resilience) is a common measure of stability that has received a large amount of theoretical attention. Yet, general expectations regarding diversity-resilience relations remain elusive. Moreover, the effects of productivity and its interaction with diversity on resilience are equally unclear. We examined the effects of species diversity, species composition, and productivity on population-and community-level resilience in experimental aquatic food webs composed of bacteria, algae, heterotrophic protozoa, and rotifers. Productivity manipulations were crossed with manipulations of the number of species and species compositions within trophic groups. Resilience was measured by perturbing communities with a nonselective, density-independent, mortality event and comparing responses over time between perturbed communities and controls. We found evidence that species diversity can enhance resilience at the community level (i.e., total community biomass), though this effect was more strongly expressed in low-productivity treatments. Diversity effects on resilience were driven by a sampling/selection effect, with resilient communities showing rapid response and dominance by a minority of species (primarily unicellular algae). In contrast, diversity had no effect on mean population-level resilience. Instead, the ability of a community's populations to recover from perturbations was dependent on species composition. We found no evidence of an effect of productivity, either positive or negative, on community- or population-level resilience. Our results indicate that the role of diversity as an insurer of stability may depend on the level of biological organization at which stability is measured, with effects emerging only when focusing on aggregate community properties.     

Accumulation of organochlorine pesticides by semipermeable membrane devices using composite complex

Semipermeable membrane devices (SPMDs) were developed for passive in situ monitoring of organochlorine pesticides (OCPs) in aqueous solution in both laboratory and field (Pearl River Delta, China) studies. The device consisted of a thin film of neutral lipid triolein, enclosed in thin-walled tubing made of composite cellulose acetate membrane (CA) supported by linear low density polyethylene (LLDPE) (CAPE). Results from the laboratory and field application indicated that triolein-CAPE (TCAPE) could quickly and efficiently accumulate hydrophobic OCPs in water and uptake equilibrium could reached within 20h in the laboratory. Some mathematical relationships of TCAPE-water partition coefficient (logK(sw)), triolein-water partition coefficient (logK(tw)) and octanol-water partition coefficient (logK(ow)) were developed under the laboratory conditions. A good correlation of accumulation in TCAPE with r(2) values ranging from 0.55 to 0.86 for individual OCPs (n=8) and an excellent correlation of logK(sw) and logK(ow) was also obtained under the field conditions. The average OCPs concentration in the surface water could be estimated by measuring OCPs concentration in the device under the field conditions.     

变频调速PLC群控系统在消防供水系统中的应用

介绍了日本三菱公司生产的FXON60MR·PLC可编程控制器与FHF15K型变频器、SR70型智能PID控制器的组合在中原油气高新股份有限公司天然气处理厂消防供水系统中的应用。通过制定合理的控制方案实现了消防供水的全自动控制,并通过控制功能的设置实现较为复杂的系统开发和应用。     

超支化水煤浆分散剂的合成与性能研究

以甲醇为溶剂,采用发散合成法,以脱氢枞胺、丙烯酸甲酯和乙二胺为原料,通过迈克尔加成反应和酰胺化缩合反应合成了一种低代超支化分子骨架.以这种低代超支化骨架为起始剂,与氯乙酸反应制备了一种新型的松香基超支化水煤浆分散剂.采用红外光谱和核磁分析对产物进行结构表征,同时用这种新型的分散剂对陕西神府煤制浆,考察了制得的水煤浆的表观黏度、Zeta电位和稳定性等性能.结果表明:松香基超支化水煤浆分散剂可以制备具有较高质量分数的水煤浆,在浆体质量分数为67％,分散剂用量为0.4％(分散剂占浆体的质量分数)时,水煤浆黏度仅为980 mPa·s.这种新型分散剂明显改善了水煤浆的成浆性能,增强了浆体的静态稳定性,并具有很好的降黏效果.