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Studi Awal Sintesis ZnO/SiO2 dengan Silika dari Limbah Padat Geothermal dan Uji Performansinya dalam Penghilangan Metilen Biru : Preliminary Study of ZnO/SiO2 Synthesis with Silica from Geothermal Solid Waste and Its Performance Test in Methylene Blue Removal Paramitha, Tifa; Joko Suryadi; Rahma Ardelia Raissa; Teguh Aditya Nugraha; Nirmala Utami
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 3 (2023): December Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2023.v9.i3.16557

Abstract

Industrial development impacts environmental problems, such as the emergence of wastewater containing methylene blue. In this research, SiO2 was composited with ZnO to remove methylene blue. The steps of this study include SiO2 extraction from geothermal solid waste, ZnO/SiO2 synthesis, and methylene blue removal test. The process of extracting SiO2 from geothermal solid waste used the sol-gel method. The FTIR analysis showed that SiO2 contains siloxane group (Si-OH) and silanol group (Si-O-Si). ZnO/SiO2 synthesis was done by making SiO2 suspension and continued with adding the addition of several Zn(NO3)2.6H2O. The FTIR analysis of ZnO/SiO2 showed no absorption at the wavenumber 960 cm-1 and there is a shoulder around the number 950 cm-1 which indicates the vibration of Si-O-Zn. Meanwhile, methylene blue removal tests were carried out on artificial wastewater. Based on the research results, the highest percent removal (99%) was obtained under operating conditions, including a dose of 500 mg/L, pH 10, and contact time of 30 minutes. Based on box-benkhen analysis, it is known that dose and pH singularly affect the percent removal, while contact time does not affect the percent removal. The optimization results obtained optimum conditions for methylene blue removal at a dose of 581.952 mg/L, pH of 10, and contact time of 30 minutes. Percent removal in conditions without irradiation and with irradiation of UV light were 98.758% and 99.178%. It shows that the adsorption process is the main process in removing methylene blue, while the photocatalytic process has little effect because it is possible that only a small amount of ZnO can attach to the surface of SiO2.
The Effect of Solvent-to-Coffee Ratio on Caffeine Content in Ethyl Acetate Extracts of Arabica Gayo Coffee Beans Soeswanto, Bambang; Sihombing, Rony Pasonang; Suryadi, Joko; Hariyadi, Tri; Paramitha, Tifa; Yusuf, Yusmardhany; -, Alfiana Adhitasari
KOVALEN: Jurnal Riset Kimia Vol. 9 No. 3 (2023): December Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2023.v9.i3.16573

Abstract

This paper studies the optimal ratio that gives the highest caffeine amount and improves the efficiency and quality of extraction from Arabica Gayo coffee beans. No previous studies have explored the best ratio of Gayo Arabica coffee beans to ethyl acetate solvent for extracting caffeine. The paper explains the method used, which has four main steps: preparing materials, extracting and measuring caffeine, and analyzing the results. The paper presents the experimental findings and discusses how different ratios affect caffeine content in Arabica Gayo coffee beans. It uses statistics to show significant differences between the ratios and compares them using Tukey tests. The paper concludes that the best solvent-to-coffee ratio for maximizing caffeine in ethyl acetate extracts is 1:5, resulting in a concentration of 1411.1 ppm. This ratio gives the best balance between caffeine yield and solvent usage.
The Effect of Variations in Sulfuric Acid - Oxalic Acid Electrolyte Concentration and Additional Aeration on 1100 Series Aluminum Anodization Results Leoanggraini, Unung; Irianto, Indra; Aji, Restu; Paramitha, Tifa; Sihombing, Rony
Journal of Green Science and Technology Vol 8 No 2 (2024): Journal of Green Science and Technology Vol.8 No.2 September 2024
Publisher : Faculty of Engineering, Universitas Swadaya Gunung Jati

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33603/jgst.v8i2.9425

Abstract

Aluminum is one of the materials used in making various types of goods because it has good properties such as being light, ductile and has good corrosion resistance. One of the disadvantages of aluminum is its low level of hardness. This can be overcome by treating aluminum, one of which is the anodization process. In this research, variations in the type of electrolyte used were sulfuric acid-oxalic acid, the electrolyte concentration was 16% with an interval of 0.5, the temperature used was room temperature with a current density of 3/dm2 and a coating time of 30 minutes. The aim of this research is to determine the acid concentration and the effect of the aeration system on mechanical properties. From the data obtained, it was found that the difference in weight of the best metal with the addition of aeration at a concentration of 13.5+2.5 was 0.0411 gr. This shows that as the concentration of oxalic acid increases it can accelerate the process of aluminum oxide formation, then for electrolyte concentrations of 16+0, 15.5+0.5, 15+1, 14.5+1.5 and 14+2 the difference in mass weight metals increased respectively by 0.0337 gr, 0.0335 gr, 0.0366 gr, 0.0390 and 0.0411 gr. In the anodization process without   additional aeration, the best metal weight difference is found at an electrolyte concentration of 13.5+2.5 of 0.0401 gr. This shows that increasing the concentration of oxalic acid can accelerate the process of aluminum oxide formation. Then at electrolyte concentrations of 16+0, 15.5+0.5, 15+1, 14.5+1.5 and 14+2 the difference in metal mass weight gradually increases by 0.0182 gr, 0.0293 gr, 0.0318 gr, 0.0322 and 0.0362 gr. Keywords: Aluminum, Anodization, Oxide Coating, Electrolyte Solution, Sulfuric Acid, Oxalic acid
Utilization of Coconut Shell and Coffee Grounds as Briquettes Using the Carbonization Method Adhitasari, Alfiana; Manfaati, Rintis; Paramitha, Tifa; Zahwa, Keisya Adellia; Setiawan, Kiranna Shalmadevy; Yusuf, Yusmardhany
Eksergi Vol 22 No 3 (2025)
Publisher : Prodi Teknik Kimia, Fakultas Teknik Industri, UPN "Veteran" Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31315/eksergi.v22i3.15128

Abstract

Biomass-based briquettes offer a renewable energy alternative that can help reduce CO₂ emissions. Coconut shells and coffee grounds are promising waste materials due to their high calorific value. This study aimed to optimize the composition and carbonization time in producing briquettes from these two materials. The briquettes were prepared following SNI 01-6235-2000 and export briquette standards. The process included drying, carbonization at 300 °C for 60, 90, 120, 150, and 180 minutes, sieving, mixing, molding, and drying. Coconut shells and coffee grounds were mixed at weight ratios of 9:1, 8:2, 7:3, 6:4, and 5:5 with a total of 46.5 grams and 8.5 grams of adhesive. Briquette quality was evaluated based on moisture content, ash content, volatile matter, density, calorific value, and fixed carbon. The 9:1 composition yielded the highest calorific value of 6,472 cal/g, while a carbonization time of 90 minutes produced the best calorific value of 6,504 cal/g. The results show that a high proportion of coconut shells with limited coffee grounds and optimal carbonization time can produce briquettes with high energy potential, suitable for use as an alternative fuel.