Jurnal Rekayasa Proses

Pengaruh kalsinasi terhadap karakteristik mesoporous nanosilica (MSN) dari sludge geothermal dan performanya dalam sistem drug loading kurkumin

Annasthasya Milleni Angelia — 2025-10-31

This study was conducted to study the effect of calcination on the characteristics of mesoporous nanosilica (MSN) from sludge geothermal waste and its performance in drug loading curcumin. The preparation of MSN was carried out using the sol-gel method using polyvinylpyrrolidone (PVP) surfactant. The removal of surfactants from MSN was processed using the calcination method, where the muffle furnace was adjusted at a temperature of 600^oC for 7 hours. The formed MSN samples were then characterized using XRF, XRD, FTIR, and BET instruments. Meanwhile, the adsorption capacity of MSN to curcumin before and after calcination was measured using a 600 ppm curcumin solution. This drug loading process lasted for 6 hours at room temperature. The study's results showed that MSN's composition and crystallinity structure did not change significantly due to the calcination process. However, the functional groups of MSN changed after calcination. The pore size of MSN after calcination also decreased from 4.31 (before calcination) to 4.02 nm. This change in MSN characteristics also affects the performance of curcumin drug loading. This can be seen based on the efficiency of curcumin adsorption, where calcined MSN can adsorb curcumin by 32.92%, while for uncalcined MSN, the adsorption efficiency is 25.64%. Based on the results of this study, the calcination process has a positive effect on the drug loading ability of MSNs.

Dual-synergistic effects of citric acid on atmospheric leaching of manganese ores

Widi Astuti — 2025-10-31

In the current study, a leaching of manganese from Indonesian manganese ores using citric acid as leaching reagent without the addition of reducing agent was investigated. Citric acid was being used as a leaching reagent and reducing agent at same time due to its reducing power. Several leaching parameters were investigated to obtain the optimum condition of citric acid leaching of manganese from those manganese ores. Low grade manganese ores from two mining areas in Indonesia contained 36.77% Mn (WK ore) and 12.5% (TG ore) with different mineral types can be leached using citric acid as leaching reagent without addition of reducing agent. The optimum manganese recovery was obtained at around 76% and 69% respectively for WK ore and TG ore with citric acid of 1M, 5% of pulp density, 150 rpm of shaker speed, 30^oC of leaching temperature, 1 hour of leaching period, and <75 µm of ore particle size. This condition was also selective for iron recovery leaching. This experiment proves that citric acid has a dual-synergistic effect as an effective leaching reagent and reducing agent at the same time for manganese leaching from manganese ores.

Nickel recovery from nickel-containing spent catalyst using atmospheric leaching and oxalate precipitation

Widi Astuti — 2025-10-31

A study has been done to investigate and optimize the recovery of nickel from nickel-containing spent catalyst through sulfuric acid (1 - 2 mol/L) atmospheric leaching in different operation conditions. From the leaching experiments, it was possible to extract 77.95% nickel under the conditions of 2 mol/L H₂SO₄, reaction time of 5 h, 5% pulp density, and temperature of 80°C. In the next step Ni was selectively precipitated from a sulfuric acid-leached solution using 1 mol/L oxalic acid. The nickel content in the product was 97.29% Ni. Based on the study, sulfuric acid was found to be a suitable leaching agent to extract Ni from the nickel-containing spent catalyst. The study also indicated the effective extraction and recovery of nickel which was well supported by characterization studies using XRD technique.

Analisis CFD unjuk kerja kolektor photovoltaic/thermal berdasarkan metode pendinginan permukaan atas dan bawah

Amrizal Nalis — 2025-10-31

This research analyses the effect of radiation and fluid mass flow rate variations on the thermal performance of Photovoltaic/Thermal (PV/T) collectors based on top-surface cooling and bottom-surface cooling methods. This research uses the ANSYS Fluent simulation method based on radiation variations of 500 W/m², 750 W/m², 1000 W/m², 1250 W/m² and fluid mass flow rates of 0.02 kg/s, 0.04 kg/s, 0.06 kg/s. The research results show that cooling the top surface is proven to be more effective than cooling the bottom surface. The highest temperature difference between top and bottom cooling for PV surface temperature is 2.64 ^oC at a mass flow rate of 0.04 kg/s and radiation of 1250 W/m2, meanwhile, the difference in average working fluid temperature is lower than 1 ^oC. For a three-fold increase in fluid flow rate from 0.02 kg/s to 0.06 kg/s, the respective temperature decrease for the PV surface and working fluid is 7% and 14% respectively for both types of working fluid flow.

Optimization of co-firing briquette fuel from coal waste and palm kernel shells: Enhancing energy efficiency and waste valorization

Salomo Pranata Aji — 2025-10-31

The low-rank coal is increasing every year but still slightly exploited by the industry, due to it being caused by the low-calorie value of the low-rank coal waste. Therefore, the mixture of other biomass is expected to raise the calorie value. This approach could potentially make the low-rank coal more economically viable for use in various industries, especially as a source of energy. Additionally, further research and development in this area could lead to more efficient and sustainable energy production methods. The study uses the Central Composite Design with ratio of low-rank coal waste and palm kernel shells of 40%: 60%, 60%: 40%, and 80%: 20% and variations of the glue starch (5 to 7%), which have been optimized and validated using the Response Surface Method approach. The results of the study showed volatile matter, fixed carbon, and calorie values of 61.43% to 71.69%, 16.56% to 26.98%, and 5190.44 to 6330.40 kcal/g, respectively. The results also demonstrated that the glue with 6% variation showed the highest fixed carbon content and calorie value in comparison to the other variations. The optimum of concentration of low-rank coal and palm kernel shell for co-firing of 80: 20% with 5% glue addition resulting in a volatile matter, fixed carbon, calorie value, flame capacity, flammability, of 54.41%, 33.39%, 6192.123 kcal/g, 14.12 min, and 0.052 g/min, respectively. The validation process also met the requirements for SNI 01-6235-2000 and SNI 8675-2018. Overall, the study concluded that the co-firing of low-rank coal waste and palm kernel shell with glue starch can result in an optimized fuel mixture with high performance characteristics. These findings are significant for industries looking to improve their energy efficiency and reduce emissions.

Different concentrations and solubility of active lime (CaCO3) on the quality of indigo paste from Indigofera longiracemosa Boiv.ex. Baill

Muzzazinah — 2025-10-31

This research aims to determine the effect of differences in concentration and solubility of active lime (25% and 35% CaCO₃ solution, 25% and 35% CaCO₃supernatant) on the quality of indigo (Indigofera longiracemosa) dye paste. The method for making indigo dye paste includes the process of soaking fresh leaves and twigs of I. longiracemosa in water, fermentation with an active lime solution of CaCO₃ with varying concentrations and solubility, settling, and filtration to obtain indigo paste. Several tests were carried out to evaluate the quality of the color in the fabric and the indican content in the indigo produced. The indican content that was successfully tested showed the highest results in the paste treated with 25% CaCO₃. Color quality tests on fabrics show that fabrics dyed with indigo paste with 35% CaCO₃solution treatment have the best color fastness to sweat with an average value of 4. The color fastness test to heat on fabric dyed with indigo paste with all types of treatment received a score of 4-5, which indicates excellent color fastness, does not fade, and does not stain other fabrics. The differences in concentration and solubility of CaCO₃ solution result in variations in the physical characteristics of indigo paste, the colors produced on fabric, the indican content, as well as the colorfastness to sweat and heat.

Utilization of cherry leaves (Muntinga calabura L) in environmentally friendly textile dyeing

Ainur Rosyida — 2025-10-31

Cherry leaves can be used as a textile dye due to their content of flavonoids and tannins that produce a yellow color on the cotton fabric. Improving dyeing results can be achieved by selecting the appropriate mordant type and mordanting method, as cherry leaves are classified as mordant dyes. This study aims to determine the effect of varying pre-mordanting times and dyeing times on the dyeing results of cotton fabric with cherry leaf extract. The dyeing process began with mordanting the fabric using Polyaluminium chloride (PAC) various times: 30, 45, 60 minutes, followed by drying. The fabric was then dyed at room temperature for varying times: 60, 90,120 minutes, followed by washing and drying. To assess dyeing quality, the fabric was tested for color strength (k/s), wash fastness, and rub fastness. Data analysis using two-way ANOVA showed that variations in pre-mordanting time and dyeing time did not significantly affect color strength, wash fastness, or rub fastness values. The dyeing results with 9 different processing conditions yielded yellow colors with varying k/s, ranging from: 4.43-5.57. The wash fastness test showed a fairly good average color change (GS: 3), and the color staining was good (SS:4-5). The dry rub fastness test showed very good average staining (SS:5), while the wet rub fastness also demonstrated good staining (SS:4-5). . The use of PAC mordant and pre-mordant methods are considered the right choice to improve dyeing results. The results indicate that cotton fabric dyed with cherry leaf extract, using pre-mordanting with PAC, without heating, and with a single dyeing process, can achieve good quality and can be applied in the textile industry/craft to produce quality and environmentally friendly products.