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.

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.

In the present study, we tackle the sustainable batteries topic by addressing its most defining aspects, namely what kind of waste material should be employed and its treatment for realizing performant battery anodes. In this regard, we focus on leather shaving waste (LSW), as it is an important waste element in many economies, resulting in an advantageous choice both from an environmental point of view and in terms of the circular economy. Herein, especially metal-free LSW is used to introduce an innovative kind of eco-friendly anode for lithium-ion batteries (LIBs). A pyrolysis process of the waste material is adopted to form biochar, followed by its texture engineering through either steam or CO₂, both of them recognized as safe and environmentally friendly procedures. Indeed, these procedures develop hierarchical micro/mesopores in the biochar and modify the amount of oxygen-containing functional groups on its surface, which can lead to high-performance anodes. In this respect, when a water-based solvent and carboxymethyl cellulose (CMC) binder are employed, the fabricated electrode discloses high initial capacities and remarkable electrochemical stability in lithium-metal half-cells. In particular, the steam-activated electrode demonstrates a specific discharge capacity of 735 mA h g⁻¹ after 1000 charge and discharge cycles at 0.5 A g⁻¹. This anode electrode also secures an excellent initial capacity and acceptable cycling stability in full-cell LIBs where a high mass LiFePO₄ loading cathode is employed. The results reported here represent a noticeable improvement with respect to the state of the art, hence demonstrating the enormous potential associated with the green re-use of waste materials in important sectors such as energy storage.