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All Journal G-Tech : Jurnal Teknologi Terapan
Caecilia Pujiastuti
Universitas Pembangunan Nasional “Veteran” Jawa Timur, Indonesia
Computer Science & IT Decision Sciences, Operations Research & Management Energy Engineering

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Briket Arang dari Limbah Tempurung Kemiri dan Serbuk Gergajian Kayu Sengon dengan Perekat Arpus (Gum Resin) Menggunakan Proses Karbonisasi Raffi Abimanyu; Farhan Muhammad Zuhdi; Mutasim Billah; Novel Karaman; Caecilia Pujiastuti
G-Tech: Jurnal Teknologi Terapan Vol 8 No 3 (2024): G-Tech, Vol. 8 No. 3 Juli 2024
Publisher : Universitas Islam Raden Rahmat, Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33379/gtech.v8i3.4831

Abstract

The type of alternative energy that can be used to replace non-renewable energy is biomass. Researchers will focus on making biomass, namely making charcoal briquettes from candlenut shell waste and wood sawdust, where these two basic materials have very good potential to be used as basic materials for making charcoal briquettes. Each material is carbonized to become charcoal. The carbonized charcoal is uniform in size to 60 mesh. Candlenut shell charcoal and sawdust charcoal are mixed in a ratio of 9:1, 8:2, 7:3, 6:4, 5:5 and arpus adhesive 7, 9, 11, 13, 15 grams. The briquette samples are molded and dried. The research results obtained the highest fixed carbon value from a 9:1 composition with 15gram adhesive of 73.77% and a calorific value of 5375.25 cal/g. These results have met quality standards according to SNI No.1/6235/2000.
Study of Crystallization Process of Potassium Chloride (KCl) Solution with Ethanol Solution Selvia Sofi Yanti; Muhimatur Rosida; Ketut Sumada; Caecilia Pujiastuti; Suprihatin Suprihatin
G-Tech: Jurnal Teknologi Terapan Vol 9 No 1 (2025): G-Tech, Vol. 9 No. 1 January 2025
Publisher : Universitas Islam Raden Rahmat, Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.70609/gtech.v9i1.5628

Abstract

This study develops a method for producing KCl fertilizer from KCl waste generated during the industrial production of calcium oxide, with KCl concentrations in the wastewater ranging from 7-10%. The main objective of this research was to investigate the effect of ethanol concentration and crystallization time on pore diameter, KCl content, and the amount of product produced. The study was conducted in two stages: evaporation and crystallization. In the evaporation stage, the KCl waste was heated until it reached a saturated solution. In the crystallization stage, ethanol solution was added as an antisolvent to accelerate the crystallization process.KCl analysis results showed that increasing ethanol concentration and crystallization time led to higher K and Cl content in the final product. The highest K content was 79.55%, and the highest Cl content was 16.88%, achieved with 90% ethanol concentration and a crystallization time of 100 minutes. BET analysis indicated that as ethanol concentration increased, the resulting product size grew larger, leading to smaller pore diameters. At high ethanol concentrations, the KCl crystals formed lacked pores. SEM-EDX analysis revealed that the KCl crystals not only contained K and Cl but also other elements such as C, O, and Ca.
Study on Microcrystalline Cellulose Derived from Cassava Stems with Variables of Sulfuric Acid Concentration and Hydrolysis Temperature Rafitrah Rizqullah; Muhammad Fadilah; Caecilia Pujiastuti
G-Tech: Jurnal Teknologi Terapan Vol 9 No 3 (2025): G-Tech, Vol. 9 No. 3 July 2025
Publisher : Universitas Islam Raden Rahmat, Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.70609/g-tech.v9i3.7457

Abstract

This study develops a method for producing microcrystalline cellulose (MCC) from cassava stem waste, aiming to reduce dependence on imported cellulose and promote the utilization of agricultural residues. Cassava stems contain a high cellulose fraction and hold potential as a raw material for pharmaceutical-grade MCC. This study investigates the effects of sulfuric acid concentration and hydrolysis temperature on the yield and quality of the resulting MCC. The production process consists of three main stages: delignification using 25% sodium hydroxide, bleaching with 2% hydrogen peroxide, and acid hydrolysis using sulfuric acid at concentrations ranging from 1.5 N to 3.5 N and temperatures between 60°C and 100°C. The resulting MCC was characterized using Particle Size Analysis (PSA), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and organoleptic testing. The best results were obtained at 1.5 N sulfuric acid and 60°C, yielding 68.24% MCC with a cellulose content of 63.07%. PSA results showed particle sizes of approximately 25.3 µm, which comply with pharmacopeial standards. XRD and SEM analyses confirmed good crystallinity and appropriate morphology. This study demonstrates that cassava stems can be processed into MCC that meets key specifications of the British Pharmacopeia, offering a low-cost and sustainable raw material for industrial and pharmaceutical applications.
The Effectiveness of Sodium Hydroxide Precipitation in Impurity Removal during NaCl Recovery from Bittern Waste Water Indah Maharani Puspitasari; Andreansyah Brilliant Putra; Caecilia Pujiastuti; Renova Panjaitan
G-Tech: Jurnal Teknologi Terapan Vol 9 No 4 (2025): G-Tech, Vol. 9 No. 4 October 2025
Publisher : Universitas Islam Raden Rahmat, Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.70609/g-tech.v9i4.8082

Abstract

Recovery of sodium chloride (NaCl) from bittern, a by-product of salt production, is often hindered by impurities such as Mg²⁺ and Ca²⁺, which reduce NaCl purity. This study evaluated the effect of sodium hydroxide (NaOH) concentration and stirring time on NaCl recovery, using NaOH concentrations of 4.6 until 8.02 N and stirring durations of 20 until 60 minutes at a constant stirring speed of 300 rpm. The process involved NaOH addition, stirring, filtration of precipitates, and NaCl crystallization. Parameters such as impurity levels, pH, NaCl purity, and recovery percentage were analyzed. Results indicated that higher NaOH concentrations and longer stirring times generally decreased impurity levels and improved NaCl recovery. Optimal conditions 5.8 N NaOH and 50 minutes stirring yielded an impurity level of 0.0359%, NaCl purity of 89.61%, and a recovery rate of 85.57%. This study presents a novel approach by optimizing NaOH concentration and stirring time parameters to effectively minimize divalent ion contamination, thereby enhancing NaCl recovery from bittern. The findings have direct applicability in improving the efficiency of salt recovery processes in coastal salt industries, contributing to more sustainable salt production systems.
Synthesis of Calcium Phosphate from Snail Shell Waste Using the Hydrothermal Method Ananda Arif Rochman; Nazila Aulya Rahman; Sani Sani; Caecilia Pujiastuti; Ika Nawang Puspitawati
G-Tech: Jurnal Teknologi Terapan Vol 10 No 2 (2026): G-Tech, Vol. 10 No. 2 April 2026
Publisher : Universitas Islam Raden Rahmat, Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.70609/g-tech.v10i2.9325

Abstract

The utilization of biowaste as an alternative raw material has attracted increasing attention in biomaterial research. Snail shell waste, which is abundant and underutilized, contains a high calcium carbonate content and offers a unique, low-cost, and sustainable precursor for calcium phosphate synthesis, particularly for bone substitute applications. This study aimed to synthesize calcium phosphate from snail shell waste using the hydrothermal method and to evaluate the effects of pH and hydrothermal time on phase formation, purity, and particle size. The shells were calcined at 800 °C for 4 hours to produce calcium oxide (CaO), then reacted with phosphoric acid at pH 8–12 under hydrothermal conditions for 25–125 minutes. The precipitates were dried and sintered at 1000 °C for 5 hours. X-ray fluorescence analysis showed a CaO content of 99.20%. X-ray diffraction revealed calcium hydrogen phosphate, hydroxyapatite, and calcium carbonate phosphate hydroxide phases. The highest hydroxyapatite content (54%) was obtained at pH 8 and 25 minutes. Higher pH and longer processing time reduced purity. Scanning electron microscopy showed granular morphology, with particle sizes decreasing from 63 nm to 28 nm as pH increased. Although promising, the hydroxyapatite content does not yet meet RSNI3 ISO 13175-3:2012 requirements.
Co-Authors Ananda Arif Rochman Andreansyah Brilliant Putra Farhan Muhammad Zuhdi Ika Nawang Puspitawati Indah Maharani Puspitasari Ketut Sumada Muhammad Fadilah Muhimatur Rosida Mutasim Billah Nazila Aulya Rahman Novel Karaman Raffi Abimanyu Rafitrah Rizqullah Renova Panjaitan S Suprihatin Sani Selvia Sofi Yanti