Special issue “metal nanoparticles as catalysts for green applications”

This Special Issue of Processes on “Metal Nanoparticles as Catalysts for Green Applications” collects recent works of researchers on metal nanoparticles as catalysts for green applications [...

A review on the efficient catalysts for algae transesterification to biodiesel

The depletion of fossil fuel resources and increasing environmental pollution led to a trend for using alternative, clean, green, and sustainable fuel and energy resources. To attain this aim, using biomass as an alternative resource for diesel production has been a hotspot among researchers. Biodiesel has several advantages, such as being lower toxic and more renewable, and eco-friendlier than diesel from fossil fuel resources. Several edible and non-edible bio-sources were used for the production of biodiesel from the transesterification process. Algal oil as a non-edible source is considered an abundant, low cost and green substrate for biodiesel production. Various factors such as reaction conditions and the type of catalyst affect the biodiesel production process. Different catalytic systems such as basic and acidic homogeneous and heterogeneous catalysts and biocatalysts were introduced for the process in the literature, and each proposed catalyst has its own advantages and disadvantages. For instance, in spite of the lower cost and better mass transfer of base and acid homogeneous catalysts, reaction system corrosion, non-reusability, and soap formation are serious challenges of these catalysts at an industrial scale. On the other hand, acid and base heterogenous catalysts overcame the issues of corrosion and recovery, but some matters such as mass transfer limitation, high cost, and weak performance in catalyzing both esterification of FFAs and transesterification of lipids must be taken into account. In addition, bio-catalysis as a high-cost process led to a purer product formation with less side reaction. Therefore, several significant factors should be considered for transesterification catalysts such as availability, cost, reusability, stability, mass transfer, and the possibility to manage both the transesterification of triglycerides and the esterification of FFAs, selecting a catalyst with predominant pros is viable. Here, a review of the biodiesel production from algal biomass focusing on the efficient catalyst of the process is presented

Catalytic Production of Levulinic Acid (LA) from Actual Biomass

Catalytic conversion of actual biomass to valuable chemicals is a crucial issue in green chemistry. This review discusses on the recent approach in the levulinic acid (LA) formation from three prominent generations of biomasses. Our paper highlights the impact of the nature of different types of biomass and their complex structure and impurities, different groups of catalyst, solvents, and reaction system, and condition and all related pros and cons for this process

Au/ZrO2 catalysts for LT-WGSR: active role of sulfates during gold deposition

Two studies examined the effect of acculturation-contact discrepancies on well-being. Specifically, we tested the prediction that well-being will be compromised when cultural minorities' acculturation preferences are not met by the intergroup and intragroup contact in a new society. Study 1 found that for Polish immigrants (n=55) acculturation-contact discrepancies were associated with compromised well-being. Study 2 followed a cohort of international students (n=106) for a period of two academic years. Results suggested that discrepancies in students' acculturation-contact in their first year had harmful consequences for their well-being 1 year later. Overall, the two studies show that discrepancies between acculturation preferences and actual contact have negative implications for the psychological adaptation of acculturating individuals.info:eu-repo/semantics/publishedVersio

LIFE GOAST Green Organic Agents for Sustainable Tanneries (LIFE16 ENV/IT/000416)

Content: Leather manufacturing is classified as water, energy and waste intensive by the Industrial Emissions Directive (2010/75/EU). Tannery effluents, if not properly treated, cause significant damage to soil and water bodies. Over 85% of world leather production involves the traditional chrome tanning process (TCTP). The use of chrome (Cr) in the industrial processing of animal hides poses serious environmental and health problems due to the use of hazardous chemicals, the production of solid/liquid waste and air emissions. LIFE GOAST aims at demonstrating the benefits of a new tanning technology on a semi-industrial scale; the project started on July 2017 and is an ongoing investigation, and involves the competences of three direct actors in the leather industry such as GSC Group spa as chemical supplier, Conceria Pasubio as tannery and Mediochiampo as waste-water treatment agency, in conjunction with the expertise of Università di Venezia, thus forming together a model of leather industry. The technical feasibility of LIFE GOAST implementation, as well as its social and economic impact, have been monitored and compared with the TCTP in order to demonstrate the reduced environmental impacts of the new process, while producing comparable or better quality leather. The LIFE GOAST team demonstrated that it was possible to treat collagen with the GOAST technology to give stabilised collagen to be used in the leather industry. A series of leather swatches were realised in accordance with the new protocol in order to obtain preliminary information on chemical oxygen demand COD of the effluents and technical feasibility of the process. The results were remarkable: COD values were lower than TCTP and it was possible to obtain soft and firm grain leather despite a shrinkage temperature lower than chromium process. However, these preliminary results allowed to process bigger pieces of leather (quarter, half and entire) to demonstrate that the technology was reproducible and in line with the small trials. The investigation is still ongoing and the team is fully committed to focus on the objectives of the project. Take-Away: Novel and alternative tanning systems to traditional chrome tanning

Activated biochars as sustainable and effective supports for hydrogenations

Activated biochars were obtained from pyrolysis and CO2-physical activation of four different biomasses including tannery shaving waste (T), vine wood waste (W), barley waste (B) and Sargassum, brown macroalgae of Venice lagoon (A). The potential of obtained carbonaceous materials as the supports of Ni,Al catalysts was investigated in levulinic acid (LA) conversion to γ-valerolactone (GVL) as a model hydrogenation reaction. Al-containing species as the Lewis acid sites for the dehydration step were incorporated to the supports using wet impregnation or precipitation. Ni as a hydrogenation active phase was added to the supports via wet impregnation. Biochar-based supports and catalysts were characterized by AAS, elemental analysis, FTIR, N2 physisorption, XRD, SEM, EDS, TEM, He-TPD, NH3-TPD and TPR techniques. The catalysts were tested for LA hydrogenation to GVL in a batch system and aqueous medium. The results showed that Ni supported on activated biochar was not active due to a lack of Lewis acid sites for dehydration. Precipitated Al-containing species on the biochar-based supports demonstrated a better catalytic performance in the reaction compared to impregnated one because of different interactions with the support and Ni species. Among different supports, the activated biochars obtained from T and W acted as the best ones. A higher catalytic efficiency was strongly influenced by the chemical (aromaticity and stability, presence of N,O-doped and functional groups), textural (the porous texture and surface area), and morphological (higher dispersion of active phases) properties of activated biochars obtained from different biomasses with different natures