Thermoplastic Starch (TPS)/Polylactic Acid (PLA) Blending Methodologies: A Review

Polylactic acid (PLA) and thermoplastic starch (TPS) are biodegradable polymers of biological origin, and the mixture of these polymers has been studied due to the desirable mechanical properties of PLA and the low processing cost of TPS. However, the TPS/PLA combination is thermodynamically immiscible due to the poor interfacial interaction between the hydrophilic starch granules and the hydrophobic PLA. To overcome these limitations, researchers studied the modification, processing, and properties of the mixtures as a strategy to increase the compatibility between phases. This review highlights recent developments, current results, and trends in the field of TPS/PLA-based compounds during the last two decades, with the main focus of improving the adhesion between the two components. The TPS/PLA blends were classified as plasticized, compatible, reinforced and with nanocomposites. This article presents, based on published research, TPS/PLA combinations, considering different methods with significant improvements in mechanical properties, with promising developments for applications in food packaging and biomedicine.

     

Algal biomass valorization for biofuel production and carbon sequestration: a review

The world is experiencing an energy crisis and environmental issues due to the depletion of fossil fuels and the continuous increase in carbon dioxide concentrations. Microalgal biofuels are produced using sunlight, water, and simple salt minerals. Their high growth rate, photosynthesis, and carbon dioxide sequestration capacity make them one of the most important biorefinery platforms. Furthermore, microalgae's ability to alter their metabolism in response to environmental stresses to produce relatively high levels of high-value compounds makes them a promising alternative to fossil fuels. As a result, microalgae can significantly contribute to long-term solutions to critical global issues such as the energy crisis and climate change. The environmental benefits of algal biofuel have been demonstrated by significant reductions in carbon dioxide, nitrogen oxide, and sulfur oxide emissions. Microalgae-derived biomass has the potential to generate a wide range of commercially important high-value compounds, novel materials, and feedstock for a variety of industries, including cosmetics, food, and feed. This review evaluates the potential of using microalgal biomass to produce a variety of bioenergy carriers, including biodiesel from stored lipids, alcohols from reserved carbohydrate fermentation, and hydrogen, syngas, methane, biochar and bio-oils via anaerobic digestion, pyrolysis, and gasification. Furthermore, the potential use of microalgal biomass in carbon sequestration routes as an atmospheric carbon removal approach is being evaluated. The cost of algal biofuel production is primarily determined by culturing (77%), harvesting (12%), and lipid extraction (7.9%). As a result, the choice of microalgal species and cultivation mode (autotrophic, heterotrophic, and mixotrophic) are important factors in controlling biomass and bioenergy production, as well as fuel properties. The simultaneous production of microalgal biomass in agricultural, municipal, or industrial wastewater is a low-cost option that could significantly reduce economic and environmental costs while also providing a valuable remediation service. Microalgae have also been proposed as a viable candidate for carbon dioxide capture from the atmosphere or an industrial point source. Microalgae can sequester 1.3 kg of carbon dioxide to produce 1 kg of biomass. Using potent microalgal strains in efficient design bioreactors for carbon dioxide sequestration is thus a challenge. Microalgae can theoretically use up to 9% of light energy to capture and convert 513 tons of carbon dioxide into 280 tons of dry biomass per hectare per year in open and closed cultures. Using an integrated microalgal bio-refinery to recover high-value-added products could reduce waste and create efficient biomass processing into bioenergy. To design an efficient atmospheric carbon removal system, algal biomass cultivation should be coupled with thermochemical technologies, such as pyrolysis.

     

Exposure of microplastics to organic matter in waters enhances microplastic encapsulation into calcium carbonate

Environmental Chemistry Letters - Plastic pollution in water ecosystems is threatening the survival of wildlife. In particular, microplastics may be encapsulated into calcium carbonate, a crucial...     

Redox-active ligands in artificial photosynthesis: a review

Environmental Chemistry Letters - Given the rising socioeconomic issues of fossil fuels, efficient artificial photosynthesis would be an important milestone toward a sustainable world. A key step...     

Spatial and seasonal dynamics of phosphorous and physicochemical variables in the Negro River Estuary (Argentina): a preliminary approach

Environmental Science and Pollution Research - Nutrient discharge into rivers and estuaries and the factors that control it need to be further understood to decrease the risk of harmful algae...     

Feather mercury levels in beached Magellanic penguin (Spheniscus magellanicus) in northern Argentina during the non-breeding season

Environmental Science and Pollution Research - Mercury (Hg) is a great concern for marine environments. Bird feathers have been widely used to assess Hg pollution. In this study, we determine...     

Effects of exposure to environmental pollutants on mitochondrial DNA copy number: a meta-analysis

Environmental Science and Pollution Research - Exposure to environmental pollutants has been associated with alteration on relative levels of mitochondrial DNA copy number (mtDNAcn). However, the...     

Bio-based films/nanopapers from lignocellulosic wastes for production of added-value micro-/nanomaterials

Environmental Science and Pollution Research - The growing demand for products with lower environmental impact and the extensive applicability of cellulose nanofibrils (CNFs) have received...     

Acute toxicity of disinfection by-products from chlorination of algal organic matter to the cladocerans Ceriodaphnia silvestrii and Daphnia similis: influence of bromide and quenching agent

Environmental Science and Pollution Research - Algal organic matter (AOM) in water reservoirs is a worldwide concern for drinking water treatment; once it is one of the main precursors for...     

Improvement of solar photo-Fenton by extracts of amazonian fruits for the degradation of pharmaceuticals in municipal wastewater

Extracts of copoazu (Theobroma gramdiflorum), canangucha (Maurita Flexuosa), and coffee (Coffea arabica) were explored as enhancers of the solar photo-Fenton process to eliminate acetaminophen, sulfamethoxazole, carbamazepine, and diclofenac in raw municipal wastewater. The process, at pH 6.2 and 5 mg L^?1 of iron without the presence of extracts, had a very limited action (~35% of the pollutants degradation at 90 min of treatment) due to the iron precipitation. Interestingly, the extract addition increased the soluble iron forms, but only copoazu extract improved the pollutant degradation (~95% of elimination at 20 min of the process action). The copoazu extract components acted as natural complexing agents, maintaining the soluble iron up to 2 mg L^?1 even after 90 min and, consequently, enhancing the pollutant degradation. The effect of copoazu extract dose on the process performance was also assessed, finding that an iron:polyphenols (from the copoazu extract) at a molar ratio equal to 1:0.16 was the most favorable condition. Then, the process improved by copoazu extract was applied to raw municipal wastewater. Remarkably, the process led to ~90% of total pharmaceuticals degradation at 20 min of treatment. This work evidenced the feasibility of amazonian fruit extracts to improve the solar photo-Fenton process to degrade pharmaceuticals in aqueous matrices at near-neutral pH.