Hydrothemal treatment is a thermochemical process that converts biomass into a coal-like materials called hydrochar by applying elevated temperature to biomass in a suspension with water under saturated pressure for a certain time. With this conversion process, easy to handle fuel with well-defined properties can be created from biomass residues, even with high moisture content. In this research, the effects of temperature (200-330°C) and biomass to water ratio (5%-20%) at initial pressure of 1.0 MPa to hydrothermal treatment of biomass (in the form of sawdust) were examined. All samples were then characterized in terms of yield, proximate analysis, calorific value,and changes in functional groups by FTIR. Approximately 52-69% of the original material was recovered as hydrochar. The gross calorific value ranged from 5472-7032 cal/g compared 5180 cal/g in the raw material. Fixed carbon ranged from 26.035-wt% compared with 26.269 wt% in the raw material.

Coal-mining activities have well-documented adverse effects on both the environment and human health. Acid mine drainage, a pivotal concern, necessitates effective interventions. This study introduces a novel solution: a modified constructed wetlands crafted exclusively from waste materials, ensuring cost-effectiveness. The innovation yielded exceptional results, achieving a noteworthy reduction of up to 99% in heavy metal concentrations, alongside swift pH normalization. What sets this study apart is its potential beyond the laboratory setting; the utilization of waste materials and low-cost methodologies underscores its scalability and practicality. This solution addresses immediate challenges and showcases promise for real-world implementation. Moreover, the results of the study extend to its insights, which offer a comprehensive examination of the method’s reusability prospects, illuminating its sustained impacts; the recommendations for future action enhance its practical significance. This study marks a significant advancement in tackling acid mine drainage. The modified constructed wetlands, driven by cost-effective waste materials, embody scalable and sustainable potential. With its holistic outlook and strategic roadmap, this study holds the key to transforming acid mine drainage challenges, particularly in rural and developing regions.

The development of textile industry in Indonesia has been increasing rapidly. The vast and continuous development of the textile industry results in an evitable increase of wastewater. One of the wastewater ingredients that difficult to be treated is dye. Dye is a pollutant with complex aromatic structure that is difficult to degrade. There are many dyes could be used, however, methylene blue is mostly used. To treat MB, several treatment methods are available. Among the methods, adsorption has been widely applied, due to its simplicity and effectiveness. In this research, nano crystal cellulose (NCC), which has a large surface area dan better mechanical properties, was prepared from the oil palm trunk and it was proposed to adsorb the methylene blue. Briefly, the process of making NCC as a biosorbent consists of the raw material pretreatment, alkaline treatment, bleaching, hydrolysis, and sonication steps. Alkaline treatment plays an important role for extracting hemicellulose, lignin and other extractive substances, so that NCC is expected to have high cellulose purity. The alkaline treatment was conducted by extraction methode using NaOH at 80 °C for 2 hours. The result showed that the percent of removal of hemicellulose dan lignin were 50.0, 55.6, and 51.73 % for NaOH concentration of 3, 4, and 5 % (w/v) respectively. This result was also supported by the result of FTIR spectra analysis on each corresponding sample. Based on these data, it can be confirmed that the optimum NaOH concentration for alkaline treatment of oil palm trunk is 4 % (w/v). Furthermore, adsorption test of NCC using methylene blue solution gave percent removal of methylene blue in the range of 69.46-72.51%.

Utilization of nanoparticles in oil and gas sector has gained a significant interest. Silica nanoparticles is often considered as a promising chemical to improv