A Novel and Green Method for Turning Food Waste into Environmentally-Friendly Organic Deicing Salts: Enhanced VFA Production through AnMBR

In order to improve the production efficiency of volatile fatty acids (VFAs) by anaerobic fermentation of food waste and reduce the cost for the production of organic deicing salt (ODS), ceramic microfiltration (MF) membrane separation was applied in the conventional food waste fermenter to build an anaerobic membrane bioreactor (AnMBR). Results showed that the maximum VFA concentration in AnMBR was up to 55.37 g/L. Due to the fact that the MF membrane could realize in situ separation of VFAs, the recovery of VFAs could reach 95.0%; 66.6% higher than that of traditional fermentation reactors. After the application of the MF membrane, more than 20.0% of soluble COD, 40.0% of proteins, and 50.0% of polysaccharides were retained and more than 90.0% of VFAs could be transferred in a timely fashion in the AnMBR system. In addition, the enrichment effect of the MF membrane enhanced enzymatic activities such as protease, α-Glucosidase and acetate kinase, and increased the abundance of some important bacteria for organic acid generation such as Amphibacter, Peptoniphilus and Halomonas, which made a significant contribution to the yield of VFAs. After concentration, evaporation and crystallization, the melting efficiency of obtained ODS can reach more than 90.0% in chloride salts, which was 112.0% of commercial calcium magnesium acetate (CMA). When compared to chloride salts and CMA, ODS was more environmentally-friendly as it can reduce the corrosion of carbon steel and concrete significantly. This study created a new way of converting food waste into a high-value organic deicing agent, realizing the resource utilization of solid waste and reducing the production cost of organic deicing agents.

Review—Concentration Measurements In Molten Chloride Salts Using Electrochemical Methods

The electrochemical measurement of concentration in molten chloride salts is a valuable tool for the control of existing and potential industrial processes, recycling of precious materials and energy production. The electrochemical techniques commonly used to measure concentration and each techniques’ associated theory are discussed. Practices which improve measurement accuracy and precision are set forth. Exceptionally accurate and precise measurements published in the literature are evaluated based on their performance in specified concentration ranges. The strengths and weaknesses of the most accurate measurements are briefly explored. Chronopotentiometry (CP) and square wave voltammetry (SWV) are accurate and precise with low concentration measurements. SWV was accurate at low concentrations, even in multi-analyte mixtures. CP was accurate for only single analyte mixtures. Open-circuit potentiometry (OCP) is accurate and precise in single-analyte mixtures but yields large errors in multianalyte mixtures. Cyclic voltammetry (CV), chronoamperometry (CA) and normal pulse voltammetry (NPV) are accurate and precise across all concentration ranges. NPV is exceptionally well suited for measurements in melts with multiple electroactive species.

Metal Emulsion-Based Synthesis, Characterization, and Properties of Sn-Based Microsphere Phase Change Materials

A comparative study of the metal emulsion-based synthesis of Sn-based materials in two different types of molten salts (namely LiCl–KCl–CsCl and LiNO3-NaNO3-KNO3 eutectics) is presented, and the properties of Sn, Sn-Cu and Sn-Cu-Zn microsphere phase change materials prepared in chloride salts are evaluated by differential scanning calorimetry (DSC) to understand the effect of element doping. Despite a high ultrasonic power (e.g., 600 W or above) being required for dispersing liquid Sn in the chloride system, well-shaped Sn microspheres with a relatively narrow size range, e.g., about 1 to 15 µm or several micrometers to around 30 µm, can be prepared by adjusting the ultrasonic power (840–1080 W), sonication time (5–10 min) and the volume ratio of salts to metal (25:1–200:1). Such a method can be extended to the synthesis of Sn-based alloy microspheres, e.g., Sn-Cu and Sn-Cu-Zn microspheres. In the nitrate system, however, a very low ultrasonic power (e.g., 12 W) can be used to disperse liquid Sn, and the particles obtained are much smaller. At low ultrasonic power (e.g., 12 W), the particle size is generally less than 10 or 4 µm when the sonication time reaches 2 or 5 min, and at high ultrasonic power, it is typically in the range of hundreds of nanometers to 2 µm, regardless of the change in ultrasonic power (480–1080 W), irradiation time (5–10 min), or volume ratio of salts to metal (25:1–1000:1). In addition, the appearance of a SnO phase in the products prepared under different conditions hints at the occurrence of a reaction between Sn droplets and O2 in situ generated by the ultrasound-induced decomposition of nitrates, and such an interfacial reaction is believed to be responsible for these differences observed in two different molten salt systems. A DSC study of Sn, Sn-Cu, and Sn-Cu-Zn microspheres encapsulated in SiO2 reveals that Cu (0.3–0.9 wt.%) or Cu-Zn (0.9 wt.% Cu and 0.6% Zn) doping can raise the onset freezing temperature and thus suppress the undercooling of Sn, but a broad freezing peak observed in these doped microspheres, along with a still much higher undercooling compared to those of reported Sn-Cu or Sn-Cu-Zn solders, suggests the existence of a size effect, and that a low temperature is still needed for totally releasing latent heat. Since the chloride salts can be recycled by means of the evaporation of water and are stable at high temperature, our results indicate that the LiCl–KCl–CsCl salt-based metal emulsion method might also serve as an environmentally friendly method for the synthesis of other metals and their alloy microspheres.

Chlorine Release from Co-Pyrolysis of Corn Straw and Lignite in Nitrogen and Oxidative Pyrolysis

Elevated emissions of hydrogen chloride (HCl) from the combustion of biomass in utility boilers are a major issue because they can cause corrosion problems and deposit molten alkali chloride salts on boilers’ water tubes, resulting in further corrosion. Pyrolysis is a good pre-treatment for solving this problem. This work conducted pyrolysis and co-pyrolysis of pulverized corn straw and lignite coal in a horizontal muffle furnace, with compositions typical of power plant combustion effluents (5% O2, 15% CO2, 80% N2) at different temperatures. Cl compounds were monitored in fuel, flue gas, and solid production of pyrolysis. The co-pyrolysis significantly affected Cl release from fuel. Cl release from corn straw into fuel gas was reduced during biomass co-pyrolysis with lignite. Co-pyrolysis had little influence on the release of organic Cl and KCl. Furthermore, at moderate-temperature pyrolysis, O2 promoted HCl release, when compared with pyrolysis under a N2 atmosphere.

A bioassay of the toxic effects of aluminum chloride and aluminum sulfate using Auloforus (Dero furcata)

The analysis of the toxicity of aluminum salts is determined by the fact that aluminum cation is contained in drinking water, artificial dyes and additives, medicines, vaccines, aerosols, and there is also a correlation between the concentration of aluminum ion in brain tissues and clinical manifestations of Alzheimer’s disease. The article presents the results of biotesting the toxic effects of aluminum chloride and sulfate using Aulophorus (Dero furcata). Currently, the methods of bioassay do not have a generally recognized and standardized system of biological analysis, there are no unambiguous requirements that an indicator system should meet. These worms are a biotest object, because its reaction to the environment can be traced by its creation of conglomerates. The behavior of Auloforus in the experiment depends on the concentration, the time spent in aluminum solutions, as well as on the specific salt. When comparing the dynamics of the behavior of Auloforus in experimental samples of aluminum solutions, we established toxic concentrations. It was found that aluminum chloride salts have a less toxic effect than aluminum sulfate.

The effects of Heavy Metals on Microbial Biomass of Forest Soil from Tropical Deciduous Forest of Central Ganga Plain

This investigation was aimed toward assessing the impact of heavy metals on soil microbial cycles. The impacts of lead (Pb) and cadmium (Cd) at various concentrations were researched over a time of about two months. Chloride salts of Pb and Cd were added independently and in blend to soil samples at room temperature (27ºC) in various polythene packs. Samples were taken from the sacks at about fourteen days span and estimations were taken of the microbial biomass carbon (MBC). The outcomes showed that there was a significant reduction in the microbial biomass carbon for all treated soils from the second week to the 6th week. However, on 8th week, increase in microbial biomass carbon was observed. At the 6th week, 2000mgkg-1Pb and 40mgkg-1Cd gave the main reduction (P < 0.05) in microbial biomass carbon of 98%. A critical decrease in biomass carbon in metal contaminated soil demonstrated that this parameter is a decent marker of toxicity of metals on soil microflora.