Lithium-ion battery (LIB) applications in consumer electronics nowdays are rapidly growing resulting the increase of batteries solid waste containing toxic and corrosive substances for the environment. On the other hand, the main active cathode components in LIB are Lithium and Cobalt, which are hazardous and limited in nature but are valuable metals. This study aims to use bio-hydrometallurgical techniques to recover heavy metals from LIB using microorganisms to avoid toxic waste from used solvents which are usually generated in conventional chemical leaching. Filamentous fungi have an important role in secreting citric acid and several organic acids to facilitate the dissolution of metal ions from the metal solids. Self-grown fungi, Aspergillus niger isolated from waste spices (Candlenut) was used as a leaching agent. Route based on fungal activity was evaluated to optimized the detoxification and metal recovery from spent LIB in various conditions (one-step, two-step and spent medium bioleaching) in 21 days of incubation. The quantitative result of XRF and EDX analysis of battery powder before and after bioleaching confirm that fungal activities are quite effective. The maximum recovery of both metals (Cobalt and Lithium) in leached liquor reached up to 72% analyzed using ICP-OES with the one-step leaching method. With respect due to the high metal recovery, fungal leaching has proven to be an easy and cost-effective green metallurgical method for recycling heavy metals in used LIBs.

Currently, packaging especially for food is a significant concern because made of plastic, which is difficult to degrade. Cellulose nanofibers (CNFs) as the composite reinforcement are chosen as a suitable replacement for the fiber. This nanocomposite is made with the main aim of making biodegradable food packaging with other capabilities such as antioxidant, antibacterial, etc. The food packaging was next referred to as bioplastic, consisting of several components. One of the major concerns is selecting cross-linking agents in nanocomposites production. The use of essential oil extracts from plants is widespread because it has an excellent binding ability and good chemical properties. The essential oil of orange peel can be extracted and used because it contains flavonoid compounds that act as antioxidants. The CNFs were made from palm oil empty fruit bunches (EFB) using the acid hydrolysis process in the previous research. The study of this nanocomposites production successfully makes transparent bioplastic. SEM results show a surface with fewer pores filled with cellulose fiber and protein. The addition of essential oil to the film increases the cross-linking bond in the matrix, improving its mechanical properties. The bioplastic was tested its endurance when buried in soil for 6 days and showed a promising results.

Iron is a major impurity in many water resources and leads to contamination in drinking water. One technology that can be used to reduce the iron content is adsorption using activated carbon. Activated carbon can be derived from biomass including forestry and agricultural waste. To produce an economic adsorbent, the researcher used bengkirai wood sawdust waste which contains 52.9% cellulose and 24% lignin. This material is treated by physical and chemical activation to produce activated carbon. However, there is no information on the effect of the type and concentration of activator on the performance of bengkirai wood activated carbon in reducing iron content. Thus, the purpose of this research is to understand the effect of activator type and concentration on the performance of activated carbon from bengkirai wood to adsorb iron content. There are five steps in this research which are preparation, carbonization, chemical activation, characterization and performance test. The raw material is prepared by screening to get an uniform size of bengkirai wood sawdust. Then, the uniformed bengkirai sawdust is physically activated in the carbonization step by heating it in the furnace at 600°C for 2 hours. After that, the carbon is activated using acid which are HCl, HNO3, and H2SO4 with concentrations of 0.1 M, 0.3 M and 0.5 M. The characterization done in this study are iodine number test and functional group test using Fourier Transform Infrared Spectroscopy (FTIR). The final step is performance test of activated carbon to adsorb iron in the water by contacting the activated carbon into water containing iron for 1 hour. The concentration of iron in the water is measured using Uv vis spectofometry. The result shows that the carbon activation with H2SO4 0.1 M produce activated carbon with the highest iodine number compared to the other type of activator and concentration. The iodine number for this activated carbon is 839.76 mg/g. However, the activated carbon treated using HNO3 shows the best performance to adsorb iron in water.