The potential of silver tetratungstate-doped bentonite intercalated with zwitterionic surfactant for removing Rhodamine B (RhB) was evaluated by comparing three composites, namely, AB (acid-activated bentonite), AB impregnated with Ag8W4O16 photocatalyst (Ag@AB), and Ag@AB intercalated with dodecyl dimethyl betaine (BS12) surfactant (Ag@OAB) with respect to their photocatalytic adsorption performance. The AB composite was prepared by treating natural bentonite with hydrochloric acid (HCl). Next, Ag@AB was synthesized by wet impregnation of Ag₈W₄O₁₆ onto AB. Lastly, the Ag@OAB was formed by intercalating the BS12 surfactant onto the Ag@AB composite. The morphology of the composite structures was characterized using Scanning Electron Microscopy (SEM). The addition of 4% Ag (w/w) tetratungstate W4O16 and 50% CEC BS12 to AB produced RhB removal percentages of 66% and 59%, respectively, compared to 65% for AB. The maximum removal percentage was achieved at pH 4 for the AB, Ag@AB, and Ag@OAB composites with RhB removal percentages of 67%, 71%, and 44%, respectively. The AB composite showed the highest regenerative ability compared to Ag@AB and Ag@OAB, with AB maintaining RhB removal at 70% after five regeneration cycles, while Ag@AB and Ag@OAB only reached four and three regeneration cycles. The total production cost of AB is fourteen to sixteen times lower than that of Ag@AB and Ag@OAB composites. In summary, the impregnation of the Ag₈W₄O₁₆ photocatalyst onto AB, resulting in the Ag@AB composite, increases the RhB removal efficiency compared to pristine AB. In contrast, the intercalation of the BS12 surfactant in Ag@OAB composite led to a decrease in RhB removal efficiency, resulting in the lowest performance among the three composites.

Biofuel derived from vegetable oil can be utilized as a vehicle fuel with various advantages, such as renewability, environmental friendliness, and sustainable availability. One of the methods for converting vegetable oil into biofuel is hydrocracking. This study investigates Ni-Co/ZSM-5 catalyst with Ni-Co metal ratios of 1:0.5, 1:1, and 1:1.5 to examine their effects on the catalyst characteristics and performance in the hydrocracking process of palm oil into biofuel. The catalyst synthesis was carried out using the co-impregnation method with ultrasound assistance, followed by characterization using XRD and XRF. The hydrocracking process was conducted at a temperature of 450℃ and a WHSV of 0.1 min-1, while the gas product was analyzed using GC and liquid product was distilled. XRF results showed that the actual Ni-Co ratio did not significantly differ from the designed ratio. XRD analysis indicated crystal agglomeration at a 1:1.5 ratio due to competition between Ni and Co metal particles diffusing into the zeolite pores, as well as the presence of dislocations and crystal defects. Differences in catalyst characteristics resulted in variations in yield, selectivity, and gas distribution in the hydrocracking process. The catalyst with a Ni-Co ratio of 1:1.5 exhibited the highest liquid product yield and biogasoline selectivity but also produced a higher concentration of CO, CO2, and C2 gases. It is associated with the breakdown of triglycerides into fatty acids, which subsequently fragment into shorter-chain biofuel components.

Enhancing the physical properties of medicinal powders is largely dependent on the granulation process. This study investigates how the concentration of hydroxypropyl methylcellulose (HPMC) and the liquid addition technique (pouring versus syringe) interact to affect the distribution of granule sizes and its porosity in a high-shear mixer setup. Both a 5% HPMC solution and distilled water (0% HPMC) were used to granulate calcium carbonate powder. The results showed that while excessive liquid addition using the pouring method led to uneven growth and agglomeration, an increase in binder viscosity improved granule homogeneity. On the other hand, the syringe method provided more uniform granules, showing its effectiveness in achieving controlled nucleation and growth. The impact of these parameters on granule characteristics was further supported by the design of response surface plots and models made easier by statistical analysis using Design-Expert software. The study's findings provide important information for improving wet granulation methods in the manufacturing of pharmaceuticals, especially with regards to guaranteeing the stability and uniformity of the final product.

The method of bio specific affinity for separation has gained attention and continues to be developed today. The affinity precipitation technique is continuously being refined because it is simpler, less complex, and highly economical without reducing product purity. Moreover, the obtained polymers can be reused and easily scaled up. The polymer used for affinity precipitation has functional groups that can act specifically, making it known as a “smart polymer.” The hydrophilic polymer and soluble liquid can be replaced with hydrophobic ones, becoming insoluble under certain conditions such as changes in pH, temperature, ionic strength, or the addition of reagents. This study aims to utilize ligand pairs for soluble liquid polymers based on macro ligands that are easily developed for large-scale applications. The research was conducted in two stages and is ready for enzyme purification testing. First, the synthesis of NIPAM polymer was carried out, with NIPAM and AIBN as fixed variables, while MPA served as the variable. Second, PABA conjugation was performed, where the synthesized NIPAM polymer was conjugated with the PABA ligand, making PABA characterization the changing variable in this phase. The dry weight of carboxylated Poly(NIPAM) obtained was 91.3%, carboxylated Poly(NIPAM)-co MPA 0.4 was 90.4%, and carboxylated Poly(NIPAM)-co MPA 0.6 was 88.9%. In the SEM test, the morphological structure of Poly(NIPAM) showed relatively harder surfaces. In the FTIR test, a significant change was observed in the spectra at 3300-2500 cm-1, which became weaker due to the presence of carboxyl groups characterized in Poly(NIPAM). The spectrophotometer test revealed the LCST condition at a temperature of 40°C. The conjugation of PABA onto Poly(NIPAM)-co-MPA 0.6 with 50 mg PABA showed better conjugation efficiency, with a conjugation yield of 52.6%. Incorporation of PABA shows recovery of trypsin between 65-80 %.

Activated carbon is a product that has many benefits since it has a high surface area and high fixed carbon content. Currently, there is still limited research that focuses on the use of coffee pulp biomass as raw material for activated carbon due to its natural properties which poses challanges. The aim of this research is to examine the influence of the pre-treatment process using the freeze-drying method on the properties of active carbon from coffee pulp waste. The best-activated carbon products can then be applied as energy storage materials. The steps taken in this study include stages (i) washing and soaking the raw materials; (ii) drying using the freeze-drying method; (iii) pyrolysis process; and (iv) activation process. Some samples were chemically activated using a KOH solution, some were physically activated using Nitrogen at a temperature of 800 °C, and the others were activated using a mixed chemical-physical method. The results of the activated carbon characteristic test show that samples dried using a freeze dryer have quite good thermal resistance with a surface morphology that has more pores. This is supported by functional group analysis which shows a reduction in unnecessary sample compounds. This research shows that freeze-drying pre-treatment affects the properties of activated carbon and indicates that the resulting activated carbon can be used as an energy storage material.

Bio-photovoltaic (BPV) technology represents a promising innovation in renewable energy by harnessing photosynthetic microorganisms, such as microalgae and cyanobacteria, to convert solar energy into electricity. This review examines recent advancements in BPV systems, with a focus on portable applications, immobilization techniques, and hybrid system integrations. The study highlights the critical role of advanced materials, such as graphene and carbon nanotubes, in improving electron transfer efficiency and system performance. Additionally, immobilization strategies using natural polysaccharides like sodium alginate and agar are discussed for their contributions to system stability and scalability. Portable BPV systems have emerged as sustainable solutions for decentralized energy needs, including environmental monitoring and IoT-based applications. Despite their potential, challenges remain in optimizing energy output, improving long-term stability, and reducing production costs. Future directions include the integration of nanotechnology, genetic engineering of microorganisms, and hybrid BPV-solar systems to enhance overall efficiency and expand application scope. This review underscores the transformative potential of BPV technology in achieving sustainable energy goals while addressing global challenges in energy access and environmental conservation. With continued innovation and multidisciplinary collaboration, BPV systems could play a vital role in transitioning toward a cleaner and more resilient energy future.Keywords: Bio-Photovoltaic; Microalgae; Renewable Energy; Portable Systems; Hybrid BPV-Solar Systems; Nanotechnology Integration.

This study examined the application of a pilot-scale Vertical Flow Constructed Wetland (VFCW) system for secondary oil refinery effluent treatment at PPSDM MIGAS, Indonesia. The VFCW technique, known for its simplicity, minimal operational cost, and environmental friendliness, was used to reduce organic pollutants (BOD and COD) to meet the standards and minimize pollutant levels. The system, constructed with a closed pond including gravel and sand substrates, and planted with Typha angustifolia, was evaluated under Hydraulic Retention Times (HRT) of 3, 4, and 5 days. The results showed BOD removal efficiencies of 52.9%, 54.4%, and 53.6%, and COD removal efficiencies of 35.7%, 49.1%, and 47.2% for hydraulic retention times of 3, 4, and 5 days, respectively. Statistical investigation (ANOVA) showed no significant difference (P > 0.05) in BOD removal efficiencies across HRTs and COD removal for 4 and 5 days. These findings implied diminishing benefits after 4 days for organic matter removal operations. The limited BOD and COD removal, in contrast to other investigations, was due to the short acclimatization time (7 days) for the Typha angustifolia to drive oxygen sufficiency and biofilm formation. These findings underlined the capability of the VFCW system to reduce wastewater contaminants sustainably and economically in tropical areas such as Indonesia. A 4-day HRT is recommended for practical applications in refinery wastewater treatment with pollutant loads up to complement. Extended acclimatization duration and improved operational settings are recommended to enhance the performance of the VFCW. This study illustrates the feasibility of VFCW as a scalable and environmentally sustainable solution for wastewater control in the petroleum industry sector. Keywords: VFCW, organic pollutants, retention time, removal efficiency, acclimatization.

This work presents the synthesis and characterization of heterogeneous cation-exchange membranes based on polypropylene (PP) and cation-exchange resin (IER) powder, developed via melt spinning. The membranes were modified with zinc oxide (ZnO) nanoparticles functionalized with polydopamine (PDA) to enhance their electrochemical properties. The effects of varying IER content and ZnO/PDA loading on key membrane properties, including ion-exchange capacity (IEC), water uptake (WU), water contact angle (WCA), proton conductivity, water permeability, and vanadium permeability, were systematically investigated. The results demonstrated that increasing IER content improved proton conductivity and IEC, but also increased vanadium permeability. The PP/ZnO-PDA (Z-2.5) membrane, with 2.5%-wt. ZnO/PDA, showed reduced water permeability (0.46 L·m⁻²·h⁻¹·bar⁻¹) and vanadium permeability (5.67 × 10⁻⁵ cm² min⁻¹), while maintaining moderate proton conductivity (13.17 mS/cm). However, increasing ZnO/PDA content beyond 2.5%-wt. led to declines in WU, IEC, and proton conductivity, likely due to nanoparticle aggregation reducing access to ion-exchange sites.

Scandium (Sc) is a strategic metal for its increasing demand for advanced materials applications. As a by-product of alumina production, bauxite residues possess a potential source of Sc. However, its high iron content hinders the Sc extraction efficiency. This study investigated the feasibility of Sc extraction from bauxite residue using hydrochloric acid (HCl) leaching process, with and without the addition of ethylenediaminetetraacetic acid (EDTA) as a chelating agent. Bauxite residue samples were characterized for their elemental composition using the X-ray fluorescence (XRF) spectroscopy. Subsequently, leaching experiments were conducted using 6M and 9M HCl solutions. The effect of EDTA on Sc extraction yield and iron dissolution was assessed. The XRF analysis revealed a significant iron content in the bauxite residue, confirming the need for effective iron removal. Hydrochloric acid was found to be effective in leaching iron (Fe) from bauxite residue, as confirmed by the high Fe content in the leachate, and a higher HCl concentration led to a higher Sc2O3 concentration in the residue. Although the addition of EDTA was effective in chelating iron, it also reduced Sc extraction efficiency. The leaching results suggested the use of 9M HCl without the addition of EDTA as the best leaching solution for Sc extraction, yielding a higher Sc recovery compared to extractions using 6M HCl and EDTA. These findings contribute to the understanding of Sc extraction from bauxite residue and provide valuable insights for developing efficient and sustainable recovery processes.

Local Microorganisms (LMO) are fermentation solutions made from agricultural, plantation and household organicwaste. LMO is made by mixing three main sources of ingredients, namely a glucose source, a complex carbohydratesource, and a microorganism source which are next fermented anaerobically. The LMO solution made can be usedto reduce plastic pollution through biodegradation. This research aims to analyse the variation of the volume of LakeToba water as a source of microorganisms in making LMO which is used to degrade plastic and to identify plasticdegrading local microorganisms. The research methodology consisted of making standard curves and growth curves,making LMO, testing the biodegradation of Low-Density Polyethylene (LDPE) plastic, isolating microorganisms,performing biochemical test, testing the clear zone for plastic degrading microorganisms, and identifyingmicroorganisms. LMO was made by mixing raw materials according to the ratio of microorganism volume tosubstrate namely 20:80 (% v/v); 30:70 (% v/v); and 40:60 (% v/v) which were fermented for 99 hours at temperatureof 37 C. The results show that there is a change in LMO pH before and after fermentation namely from 4.75; 4.9;and 4.94. to 3.46; 3.45; and 3.48. The decrease in pH occurs due to the activity of microorganisms that producedorganic acids. The three variations of LMO produce degradation percentage of LDPE plastic, namely 2.353% w/w;3.012% w/w; and 4.023% w/w. The variation ratio of 40:60 (% v/v) shows the largest percentage of LDPEdegradation, which was then isolated, and 5 isolates were obtained. The five isolates were also screened to validatetheir potential in degrading LDPE and 2 isolates were found which produced clear zones which were identified bygram staining as Staphylococcus aureus and Streptococcus sp.