Engineering supramolecular artificial edifices designed for a specific function

The Langmuir-Blodgett technique and its variants (alternate layers, self-organising mixtures, the semi-amphiphilic technique, the peculiar solid state chemistry in L.B. films) are collective methods which allow physical chemists, with a very small amount of synthetic chemistry, to build up molecular assemblies exhibiting not only the properties of each of their components, but also extra properties which arise from the architecture: cooperativity, anomalous chemical properties, molecular recognition, etc. These new tailored molecular edifices are the basic “brick” of tomorrow's molecular electronics and fine chemistry. These strategies are exemplified here by two active supramolecular edifices which have been successfully designed and built up: an artificial dioxygen trap based on the same principle as hemoglobin, and one molecule thick conductors. Promising applied results have already been obtained in the field of gas sensing with these new conductors, owing to molecular architectural amplification.     

A hybrid anaerobic solid-liquid bioreactor for food waste digestion

A hybrid anaerobic solid-liquid (HASL) bioreactor is an enhanced two-phase anaerobic system, that consists of a solid waste reactor as the acidification reactor and a wastewater reactor, i.e. an upflow anaerobic sludge blanket (UASB) reactor as the methanogenic reactor. Food waste digestion in HASL bioreactors with pre-acidification and HASL operation stages was investigated in two separate runs. After 8 days of pre-acidification in Run A and 4 days in Run B, total volatile fatty acid (TVFA) and chemical oxygen demand (COD) concentrations in the leachates of both acidification reactors were similar. During HASL operation stage, TVFA and COD removal in the methanogenic phase were 77–100% and 75–95%, respectively. Some 99% of the total methane generated was from the methanogenic phase with a content of 68–70% methane. At the end of operation, about 59–60% of the added volatile solids (VS) were removed with a methane yield of 0.25 l g^–1 VS.     

Monitoring the natural attenuation of a sewage sludge toxicity using the Allium cepa test

Appropriate final disposal of sewage sludge (SS) generated by wastewater treatment plants (WWTP) has been considered a serious environmental problem, but also a viable alternative to be applied in agriculture, once SS is rich in organic matter and nutrients. However, SS can be a source of contamination of several toxic agents. Therefore, its use in agriculture requires special care to avoid possible damage to the environment and exposed organisms. Detoxification of toxic wastes can be performed using the monitored natural attenuation, which involves biological, physical and chemical processes that frequently occur in the environment. This study aimed to assess the feasibility of decontaminating SS after different periods of monitored natural attenuation. To this end, samples of SS and associations of soil/SS with proportions of 10, 25 and 50% SS were buried for 0, 2, 6 and 12 months in holes prepared in a place free of contamination. Allium cepa was used as an indicator to assess the efficiency of the natural attenuation process. According to chemical analysis, the SS samples presented a high concentration of m- and p-cresol, especially for samples analyzed after 0 or 2 months of natural attenuation. The microorganisms present in the SS belonged to 17 different genera of bacteria, which varied in the microbial composition among samples. Both, raw SS and aqueous SS extracts induced DNA damage in A. cepa, even when associated with soil. However, this effect was observed to decline during the attenuation period, although significant effects were detected for the highest tested concentration (100% SS) even at the end of this process. These results thus indicated the necessity of applying a stabilization process associating SS and soil for a period of at least 12 months and showed that the studied raw SS is not a viable material for use as a soil reconditioner, even after natural attenuation. A. cepa test proved to be a useful tool to assess the efficiency of SS detoxification process. Therefore, we suggest that the application of SS in agriculture should be approached with caution and that the SS must be previously submitted to methodologies that evaluate its toxic potential.     

Biofilter performance and characterization of a biocatalyst degrading alkylbenzene gases

A biofilter treating alkylbenzene vapors was characterized for its optimal running conditions and kinetic parame-ters. Kinetics of the continuous biofilter were compared to batch kinetic data obtained with biofilm samples as well as with defined microbial consortia and with pure culture isolates from the biofilter. Both bacteria and fungi were present in the bioreactor. Five strains were isolated. Two bacteria, Bacillus and Pseudomonas, were shown to be dominant, as well as a Trichosporon strain which could, however, hardly grow on alkylbenzenes in pure culture. The remaining two strains were most often overgrown by the other three organisms in liquid phase batch cultures μ _max, K_S, K_I values and biodegradation rates were calculated and compared for the difterent mixed and pure cultures. Since filter bed acidification was observed during biofiltration studies reaching a pH of about 4, experiments were also undertaken to study the influence of pH on performance of the different cultures. Biodegradation and growth were possible in all cases, over the pH range 3.5–7.0 at appreciable rates, both with mixed cultures and with pure bacterial cultures. Under certain conditions, microbial activity was even observed in the presence of alkylbenzenes down to pH 2.5 with mixed cultures, which is quite unusual and explains the ability of the present biocatalyst to remove alkylbenzenes with high efficiency in biofilters under acidic conditions.     

Use of textile waste water along with liquid NPK fertilizer for production of wheat on saline sodic soils

A field experiment in collaboration with a private textile industry (Noor Fatima Fabrics Private (Ltd.), Faisalabad) was conducted to evaluate the effect of disposed water from bleaching unit, printing unit and end drain for improving growth and yield of wheat under saline sodic soil. Textile waste water along with canal water (control) was applied with and without liquid NPK fertilizer. The application of liquid NPK fertilizer with end drain waste water increased plant height, spike length, flag leaf length, root length, number of tillers (m^?2), number of fertile tillers (m^?2), 1000 grain weight, grain yield, straw yield and biological yield up to 21, 20, 20, 44, 17, 20, 14, 44, 40 and 41%, respectively compared to canal water (control). Similarly, the NPK uptake in grain was increased up to 15, 30 and 28%, respectively by liquid fertilizer treated end drain water as compare to canal water with liquid fertilizer. Moreover, concentration of different heavy metals particularly Cu, Cr, Pb and Cd was decreased in grains by application of waste water along with liquid NPK. The result may imply that waste water application along with liquid-NPK could be a novel approach for improving growth and yield of wheat in saline sodic soils.     

New Solid Supports Linking Nucleoside Scaffolds

Abstract

An easy and efficient strategy to obtain new nucleoside based solid supports in which the nucleoside moieties have been anchored to the solid support through the nucleobase is here proposed. A simple and efficient solid-phase synthesis of 5′ and 3′-derivatized uridine analogues has so been developed, following methodologies well established in organic chemistry.     

From Life Cycle Assessment to Life Cycle Management

Life cycle assessment (LCA) is a widely accepted methodology to support decision‐making processes in which one compares alternatives, and that helps prevent shifting of environmental burdens along the value chain or among impact categories. According to regulation in the European Union (EU), the movement of waste needs to be reduced and, if unavoidable, the environmental gain from a specific waste treatment option requiring transport must be larger than the losses arising from transport. The EU explicitly recommends the use of LCA or life cycle thinking for the formulation of new waste management plans. In the last two revisions of the Industrial Waste Management Programme of Catalonia (PROGRIC), the use of a life cycle thinking approach to waste policy was mandated. In this article we explain the process developed to arrive at practical life cycle management (LCM) from what started as an LCA project. LCM principles we have labeled the “3/3” principle or the “good enough is best” principle were found to be essential to obtain simplified models that are easy to understand for legislators and industries, useful in waste management regulation, and, ultimately, feasible. In this article, we present the four models of options for the management of waste solvent to be addressed under Catalan industrial waste management regulation. All involved actors concluded that the models are sufficiently robust, are easy to apply, and accomplish the aim of limiting the transport of waste outside Catalonia, according to the principles of proximity and sufficiency.     

A New Electrolyte Formulation for Securing High Temperature Cycling and Storage Performances of Na‐Ion Batteries

The Na‐ion battery is recognized as a possible alternative to the Li‐ion battery for applications where power and cost override energy density performance. However, the increasing instability of their electrolyte with temperature is still problematic. Thus, a central question remains how to design Na‐based electrolytes. Here, the discovery of a Na‐based electrolyte formulation is reported which enlists four additives (vinylene carbonate, succinonitrile, 1,3‐propane sultone, and sodium difluoro(oxalate)borate) in proper quantities that synergistically combine their positive attributes to enable a stable solid electrolyte interphase at both negative and positive electrodes surface at 55 °C. Moreover, the role of each additive that consists in producing specific NaF coatings, thin elastomers, sulfate‐based deposits, and so on via combined impedance and X‐ray photoelectron spectroscopy is rationalized. It is demonstrated that empirical electrolyte design rules previously established for Li‐ion technology together with theoretical guidance is vital in the quest for better Na‐based electrolytes that can be extended to other chemistries. Overall, this finding, which is implemented to 18 650 cells, widens the route to the rapid development of the Na‐ion technology based on Na₃V₂(PO₄)₂F₃/C chemistry.     

Extended Producer Responsibility in Thailand

Waste electrical and electronic equipment (WEEE) sheds light on the dimmer side of production and consumption patterns in modern societies. The rapid increase in its quantity and complexity contribute to the challenges it poses to solid waste management systems. Several members of the Organisation for Economic Co‐operation and Development (OECD) have relied on the principle of extended producer responsibility (EPR) to tackle the issue, with varying degrees of success. Several non‐OECD countries, including Thailand, are now developing WEEE programs and are looking for lessons from these first movers. This case study aims to provide an understanding both of this context and of the EPR program for WEEE proposed for Thailand. It finds that EPR mechanisms in general, and the proposed buy‐back system financed by product fees in Thailand in particular, have a strong potential to consolidate WEEE collection for the formal recycling sector by offering end users monetary incentives. On the negative side, this is an expensive combination of policy instruments, and the institutional design of the governmental fund is rigid. The policy proposal also contains no mechanism for product redesign—one of the objectives in the national WEEE strategy. This article suggests that the effectiveness of the policy might benefit from more flexibility at the compliance scheme level, in order to lessen the monopoly of the governmental fund, as well as the introduction of differentiated fees to promote environmentally friendly products.