Alkoxy-silyl Induced Agglomeration: A New Approach for the Sustainable Removal of Microplastic from Aquatic Systems

The substance class of inert organic-chemical stressors (IOCS) describes organic-chemical (macro-) molecules, which demonstrate a high level of persistence upon entry in the ecosystem, and whose degradation is limited. These synthetically produced organic-chemical macromolecules, which are often derived from the polymerization of different monomers, are, in the form of plastics, indispensable in the everyday world. They enter the environmental compartments and cause great damage due to primary (industry, cosmetic, washing of textile), and secondary (degradation) entry. If these particles get into aquatic systems, this has fatal consequences for the ecosystem such as the death of marine animals, or bioaccumulation. Wastewater treatment plants are reaching their limits and require innovative ideas for the sustainable removal of microplastic. This article examines a new approach to the removal of polymers from aquatic systems (lab scale) by using sol–gel induced agglomeration reactions to form larger particle agglomerates. These enlarged agglomerates can be separated much more easily from the wastewater, since they float on the water surface. Separation systems, e.g. sand trap can easily be used. A further advantage is that the agglomeration can be carried out completely independently of the type, size, and amount of the trace substance concentration as well as of the external influences (pH value, temperature, pressure). Thus, this new type of particle separation can not only be used in sewage treatment plants, but can also be transferred to decentralized systems (e.g. implementation in industrial processes).

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Effect of ZnCl<Subscript>2</Subscript> impregnation ratio on pore structure of activated carbons prepared from cattle manure compost: application of N<Subscript>2</Subscript> adsorption-desorption isotherms

Activated carbons were prepared from cattle manure compost (CMC) by ZnCl₂ activation with various ZnCl₂/CMC mass ratios. Based on the N₂ adsorption-desorption isotherms, mathematical models including the Dubinin-Radushkevich (DR) equation, the α_s plot, and the Horvath-Kawazoe method were used to analyze the pore structural characteristics of the prepared activated carbons. It was found that for carbons possessing both micro-and mesopores, the DR method provided a more accurate estimation than the α_s method for the extent of microporosity. The effect of the ZnCl₂ impregnation ratio on the pore structure was discussed using the DR method. The results revealed that pore evolution involved three distinct regions with increases in the amount of impregnated ZnCl₂: raising the ZnCl₂/CMC mass ratio from 0.00 to 0.50 resulted in a 19-fold increase in micropore volume (V_me ^D) but caused no change in the mesopore volume (V_me ^D); increasing the ZnCl₂/CMC mass ratio from 0.50 to 1.00 led to an increment in V_mi ^D of about 50% and in V_me ^D of 170%; while raising the ratio from 1.50 to 2.50 caused a slight decrease in V_mi ^D but a 200% increment in the value of V_me ^D.     

A Multiscale Approach for Assessing the Interactions of Environmental and Biological Systems in a Holistic Health Risk Assessment Framework

Advances in computing processing power and in availability of environmental and biological data have allowed the development and application of comprehensive modeling systems that utilize a holistic, integrated, approach for assessing the interactions of environmental and biological systems across multiple scales of spatiotemporal extent and biological organization. This approach allows mechanism-based environmental health risk assessments in a person-oriented framework, which accounts for simultaneous exposures to contaminants from multiple media, routes, and pathways. The conceptual basis and example applications of the Modeling ENvironment for TOtal Risk (MENTOR), and the DOse–Response Information ANalysis system (DORIAN) are presented.     

Chemical Recovery of Useful Chemicals from Polyester (PET) Waste for Resource Conservation: A Survey of State of the Art

In this paper we present the main technologies developed over the last decades on chemical recycle of PET from a practical and economical point of view. We show details of plants used to carry out solvolitic reactions emphasising steps of purification, which are sometimes not considered when discussing chemical, recycle but which, in fact, are the key feasibility factors. The recycling or modification of PET to obtain monomers and other useful chemicals as intermediates and additives is carefully considered.     

Biogas from the organic fraction of municipal solid waste: Dealing with contaminants for a solid oxide fuel cell energy generator

The present work investigates electricity production using a high efficiency electrochemical generator that employs as fuel a biogas from the dry anaerobic digestion of the organic fraction of municipal solid waste (OFMSW).The as-produced biogas contains several contaminants (sulfur, halogen, organic silicon and aromatic compounds) that can be harmful for the fuel cell: these were monitored via an innovative mass spectrometry technique that enables for in-line and real-time quantification.A cleaning trap with activated carbons for the removal of sulfur and other VOCs contained in the biogas was also tested and monitored by observing the different breakthrough times of studied contaminants.The electrochemical generator was a commercial Ni anode-supported planar Solid Oxide Fuel Cell (SOFC), tested for more than 300 h with a simulated biogas mixture (CH₄ 60 vol.%, CO₂ 40 vol.%), directly fed to the anode electrode. Air was added to promote the direct internal conversion of CH₄ to H₂ and CO via partial oxidation (POx).The initial breakthrough of H₂S from the cleaning section was also simulated and tested by adding ～1 ppm(v) of sulfur in the anode feed; a full recovery of the fuel cell performance after 24 h of sulfur exposure (～1 ppm(v)) was observed upon its removal, indicating the reliable time of anode exposure to sulfur in case of exhausted guard bed.