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Development of effective upcycling methods for biodegradable plastic waste (for example, straws made of polylactic acid (PLA)) has emerged. In this study, a catalyst derived from sea shell waste (SSC) was used for a thermocatalytic conversion of biodegradable straw (BDS) for the recovery of monomer (for example, lactic acid). In effect, a strategy for simultaneously upcycling of biodegradable plastic waste (for example, straws made of polylactic acid (PLA)) and marine waste (for example, sea shell waste) was proposed. The SSC mainly consisted of calcium carbonate; thus, it had basicity with no acidity. Notably, a temperature of 500 °C and an SSC/BDS mass ratio of 0.5 led to the highest lactic acid recovery from BDS in this study. In particular, the use of SSC under the above-mentioned temperature and SSC/BDS mass ratio resulted in a 130 times higher lactic acid recovery than noncatalytic BDS conversion, most likely because the base sites present on SSC catalyzed the thermal cracking of PLA polymer bond. However, coke deposition was the major deactivation pathway of SSC during the thermocatalytic BDS conversion. In essence, SSC has the potential to be a catalyst used to thermocatalytically recover high-value chemicals from biodegradable plastic waste. In addition, this study can offer insight into developing waste conversion processes for the simultaneous upcycling of biodegradable plastic and marine wastes.

This work demonstrates ionic liquid electrolyte‐inscribed sweat‐based dual electrolyte functioning supercapacitors capable of self‐charging through sweat electrolyte function under a non‐enzymatic route. The supercapacitor electrodes are fabricated from TREN (tris(2‐aminoethyl)amine), poly‐3,4‐ethylenedioxythiophene, and a graphene oxide mixture with copper‐mediated chelate, and this polymer‐GO‐metal chelate film can produce excellent energy harvest/storage performance from a sweat and ionic liquid integrated electrolyte system. The fabricated device is specifically designed to reduce deterioration using a typical planar structure. In the presence of sweat with ionic liquid, the dual electrolyte mode supercapacitor exhibits a maximum areal capacitance of 3600 mF cm−2, and the energy density is 450 mWhcm−2, which is more than 100 times greater than that from previously reported supercapacitors. The supercapacitors were fabricated/attached directly to textile fabrics as well as ITO‐PET (Indium tin oxide (ITO)‐polyethylene terephthalate (PET) film to study their performance on the human body during exercise. The self‐charging performance with respect to sweat wetting time for the sweat@ionic liquid dual electrolyte showed that the supercapacitor performed well on both fabric and film. These devices exhibited good response for pH effect and biocompatibility, and as such present a promising multi‐functional energy system as a stable power source for next‐generation wearable smart electronics.

Lignocellulosic biomass is an agricultural waste material abundantly produced in large quantities on earth. Rice husk (RH) is one of the lignocellulosic biomass and a huge byproduct of rice milling. Notably, the rice plant collects silica from the soil and stores the collected silica in the form of silicic acid inside the cellulose micro-compartments of the plant. Therefore, RH obtained from rice milling contains a significant quantity of amorphous silica, which can further be used for several other purposes. Furthermore, Silica-rich RH can be employed as raw material for the production of biofuels and biochars instantaneously via thermochemical processes like pyrolysis, gasification. This article thoroughly explored the prospective method of rice husk use to produce bio silica and energy at the same time, which is currently under investigation. Moreover, this study also discussed current improvements in the synthesis of RH silica materials and their long-term uses, particularly in energy and environmental functional materials. In terms of the environment, RH-silica materials may remove heavy metals and organic pollutants in soil amendment, wastewater treatment, and gas purification via adsorption, catalysis, and integrative methods. In essence, there are numerous research and development obstacles to the production of bio silica and biofuels, respectively, from RH to overcome, and this review article highlights all of them.

There has been growing and recent interest in using non-edible feedstocks such as waste animal fats as alternate to vegetable oils in biodiesel production to address food vs fuel debate. The waste animal fats are cost effective and yield the biodiesel of good quality. Therefore, waste animal fats are appealing and excellent feedstocks to produce biodiesel. Commercially, the biodiesel is obtained by transesterification reaction of triglycerides present in oil/fat with alcohol in presence of homogeneous base catalysts. However, free fatty acids found in low-quality oil feedstocks are particularly sensitive to homogeneous base catalysts, necessitating extra acid pretreatment and neutralization procedures that not only raise the overall expense of producing biodiesel but also create environmental contamination. Optimistically, the use of solid catalysts can offer an environmentally friendly, cost-effective, and practical route for the manufacture of biodiesel from inexpensive oil feedstocks, including waste animal fat. The present review article covers catalyzed transesterification/esterification using various catalysts with particular focus on use of heterogeneous catalysts when using waste animal fat as feedstock for biodiesel production. Particularly, the properties of biodiesel obtained from waste animal fats are also compared to biodiesel properties of standard organizations such as European Committee of Standardization and the American Society for Testing and Materials. Moreover, this paper also offers future research directions that can direct researchers to fill in knowledge gaps impeding the creation of efficient heterogeneous catalysts for long-term biodiesel generation. To the best of our knowledge, the valorization of waste animal fats from slaughterhouse is not feasible and have some techno-economic concerns. However, this technology is more desirable considering environmental point of view to address the pollution problems caused by these wastes.

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The concept of a “hydrogen (H2) society” is meant to serve as a greener alternative toward fossil fuel utilization and mitigating the climate crisis. However, major challenges concerning sustainability in the production of H2 need to be resolved to fulfill the development of a hydrogen society. Climate change cannot be mitigated while fossil fuels remain the primary source of H2 production. The use of excess renewable energy to produce H2 can also be economically challenging; moreover, difficulties in storage and transportation could render a hydrogen society inviable. Biochar, as a renewable low-cost material, could be the key toward resolving these challenges, by serving as feedstock for steam gasification, as a catalyst or catalyst support for thermochemical or photochemical processes, or as an additive for biochemical processes. This study examines the plausibility of the concept of an “H2 society” and the role of biochar in making this a reality. Biochar helps improve H2 production, because it is an effective catalyst due to its high surface area, porosity, conductivity, and stability. Its high H2 storage capacity could facilitate effective stationary storage and transportation. The role of biochar in an H2 economy is becoming clearer; however, developing effective biochar-based materials for H2 production and storage is necessary.