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All Journal EKSAKTA: Journal of Sciences and Data Analysis IJCR (Indonesian Journal of Chemical Research) Industrial Innovation Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit
Wahyu Fajar Winata
Department Of Leather Processing Technology, Politeknik ATK Yogyakarta, Yogyakarta, Indonesia
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Earth & Planetary Sciences Materials Science & Nanotechnology

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Synthesis of Carbon from Rice Groats at Various Pyrolysis Temperatures and Its Application for the Recovery of Chromium Wastewater from the Tannery Industry Wahyu Fajar Winata; Ika Yanti
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 4, ISSUE 1, February 2023
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/EKSAKTA.vol4.iss1.art3

Abstract

The research on synthesis of carbon from rice groats at various pyrolysis temperatures and its application for the recovery of chromium wastewater from the tannery industry by varying pyrolysis temperatures at 300, 400, and 500 °C. The results of carbon synthesis are analyzed in the form of determination of yield, water content, ash content, and iodine number. The best pyrolysis condition with the quality requirement of carbon is at a pyrolysis temperature of 500 °C with 760 mg.g-1 (iodine number). Adsorption kinetics was also carried out to determine the adsorption kinetics of chromium ions from tannery wastewater. Adsorption kinetics model of chromium wastewater from the tannery industry corresponds to the pseudo-second-order kinetics model with R2 is 0.9857, k2 is 0.0093 g.mg-1.min-1, and qe is 28.5714 mg.g-1.
Studi Kinetika Adsorpsi Cu(II) Dan Pb(II) dengan Menggunakan Biosorben dari Polimer Ekstrak Kulit Buah Rambutan Winata, Wahyu Fajar; Yanti, Ika
INDONESIAN JOURNAL OF CHEMICAL RESEARCH Volume 5, ISSUE 1, 2020
Publisher : Chemistry Department, Universitas Islam Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (35.093 KB) | DOI: 10.20885/ijcr.vol5.iss1.art1

Abstract

RecoveryCu(II) dan Pb(II) yang sebagian besar terkandung dalam limbah cair industri, baik industri besar maupun rumah tangga telah dilakukan, salah satunya adalah dengan proses adsorpsi. Penelitian ini dilakukan studi kinetika adsorpsi Cu(II) dan Pb(II) dalam limbah cair untuk mengetahui efektivitas biosorben dari ekstrak kulit buah rambutan terhadap limbah cair yang mengandung Cu(II) dan Pb(II).Penentuan kinetika adsorpsi Cu(II) dan Pb(II) dengan menggunakan biosorben dari ekstrak kulit buah rambutan dilakukan melalui beberapa model kinetika yaitu model kinetika Langmuir-Hinshelwood,Santosa, Lagergreen dan Ho. Kinetika adsorpsi Cu(II) dan Pb(II) semuanya mengikuti model kinetika Ho, yang merupakan mekanisme kinetika orde dua semu.
Effect of Phenol–Formaldehyde Molar Ratio on the Physicochemical Properties of Phenolic Synthetic Tanning Agent (Syntan) Winata, Wahyu Fajar; Hermawan, Prasetyo; Nurbalia, Elis
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 7, ISSUE 1, April 2026
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/EKSAKTA.vol7.iss1.art10

Abstract

Phenolic synthetic tanning agents (syntans) are widely used in the leather industry due to their controllable properties and consistent performance. This study aims to investigate the effect of phenol– formaldehyde molar ratio on the physicochemical properties of syntans synthesized via sulfonation. The syntans were prepared using various molar ratios (0:1, 0.5:1, 1:1, 1.5:1, 1:0.5, and 1:0) throughcondensation followed by sulfonation. The products were characterized in terms of pH, specific gravity, viscosity, degree of sulfonation (DS), and functional groups using FTIR spectroscopy. The results show that increasing phenol or formaldehyde concentration led to higher specific gravity and viscosity, indicating increased polymerization. The pH values ranged around ~4, confirming suitability for leather processing. The DS decreased with increasing phenol or formaldehyde concentration, suggesting competition between polymerization and sulfonation reactions. The optimal molar ratio (1:1) produced the most homogeneous and stable syntan system. The pH values of all syntans were consistently around ~4, indicating suitability for leather processing. Increasing phenol or formaldehyde concentration resulted in higher viscosity and specific gravity, while the degree of sulfonation decreased significantly, confirming the trade-off between polymerization and sulfonation reactions. In conclusion, the phenol–formaldehyde molar ratio significantly influences syntan properties by controlling the balance between polymerization and sulfonation. These findings provide a scientific basis for optimizing syntan formulation and improving efficiency in sustainable leather processing.
Binder Engineering of Leather Shaving Waste–Based Collagen Composite for Shoe Insole Application: Mechanical–Moisture Trade-Off Analysis Winata, Wahyu Fajar; Nurbalia, Elis; Rahmayani, Elyka; Dewi, Zahra Saadiya; Tiyastuti, Rini
INDONESIAN JOURNAL OF CHEMICAL RESEARCH Vol. 11 No. 1 (2026): Volume 11, ISSUE 1, 2026
Publisher : Chemistry Department, Universitas Islam Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/ijcr.vol11.iss1.art6

Abstract

Leather shaving waste (LSW) generated from the tannery industry contains chromium-stabilized collagen fibers that are environmentally persistent and difficult to manage. This study investigates the valorization of LSW into leather board for shoe insole applications through binder system engineering. LSW was neutralized using alkaline treatment and compounded with polyester resin and polyvinyl acetate (PVAc), followed by press molding. Mechanical properties and water absorption were evaluated according to SNI 1294-2009 standards. The results show that binder composition significantly influences interfacial adhesion, mechanical strength, and moisture sensitivity. Formulation F3 exhibited superior tensile and tear strength due to enhanced fiber–matrix bonding, while formulation F4 demonstrated improved water resistance. An Engineering Performance Index (EPI) was introduced to integrate mechanical strength and moisture stability, revealing a clear trade-off between maximum mechanical performance and durability against water absorption. Formulation F6 presented a more balanced mechanical–moisture profile suitable for practical insole applications. These findings confirm that binder engineering governs the structure–property relationship of collagen-based composites and provides a sustainable pathway for circular utilization of tannery solid waste.
Use of Lime Suspension and Lime Water as a Solution in Goat Skin Appliance as an Initiative for Implementing Clean Products Prasetyo Hermawan; Wahyu Fajar Winata
Industrial Innovation Vol. 2 No. 1 (2025): Industrial Innovation
Publisher : Politeknik ATK Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58533/d34zmb56

Abstract

The study aimed to compare the effects of using lime suspension and saturated lime water in the goat skin liming process, focusing on solution properties and skin characteristics. Liming was conducted at 26 °C for 60 minutes using a stirrer, with a skin-to-solution ratio of 1:10 and 2 g Ca(OH)₂ per 100 ml water. The initial pH values were 11.69 (lime suspension) and 11.62 (lime water), while initial conductivity was 7439 μS/cm and 4971 μS/cm, respectively. Observed variables included pH, TDS, electrical conductivity, precipitate weight, and skin weight gain and characteristics. Results showed no significant difference in pH between treatments during liming (p = 0.075) and no significant difference in skin weight gain (p = 0.067). However, solution conductivity differed significantly (p = 0.002), with lime suspension producing higher conductivity values. At the end of liming, precipitate weights were 1.53 g for lime suspension and 0.04 g for lime water, indicating more undissolved material in the suspension method. Skin characteristics, such as color, pH, and elasticity, were similar for both treatments. The findings suggest that while lime suspension and lime water produce comparable results in terms of pH and skin weight gain, they differ in conductivity and precipitate formation. The reduced precipitate in lime water indicates a cleaner process, which could contribute to clean production practices in the leather industry by minimizing solid waste without compromising leather quality. This research provides a scientific basis for considering saturated lime water as an alternative to lime suspension, potentially reducing environmental impact while maintaining product performance in goat skin leather processing. 
UPGRADING PROCESS FINISHING GRAIN CRACKS ON COW CRUST LEATHER CORRECTED GRAIN BOX UPPER ARMY SHOES Wahyu Fajar Winata; Nabilla Indrakusuma; Nais Pinta Adetya
Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit Vol. 22 No. 2 (2023): Berkala Penelitian Kulit, Sepatu dan Produk Kulit
Publisher : Politek ATK Yogyakarta Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58533/xavr9d57

Abstract

Crust-dyed leather is a product that has gone through the process of beam house operation, tanning, and post-tanning but has not gone through finishing. The purpose of this study is to overcome these problems by upgrading the finishing process to cover broken grain defects. The raw material used is rejected quality crust cowhide leather with 1 side broken grain defects. The finishing process upgrading method used to overcome this problem is buffing using 240-size sandpaper to erode broken grain parts to make them more disguised and impregnation with water, acrylic polymer (2350 RE), and penetrator (Biofin AU BK) 64). The impregnation solution can coat the cracked crust grain parts by forming new grains which have high shatter resistance properties. The results of leather testing after upgrading were carried out at the Rubber and Plastic Leather Center, Yogyakarta, obtained results that were following ISO 3379: 2015 standards, namely distension of grain at a crack of 8.60 mm and grain crack load of 467.28 N. It can be concluded that the buffing and impregnation in upgrading the finishing process can overcome the problem of cracked CGB upper army shoe grain crust cow skin and has met the burst resistance test standard ISO 3379:2015.
RE-DYEING PROCESS ON CABRETTA SHEEPSKIN GOLF GLOVES TO IMPROVE COLOR FASTNESS USING ALIPHATIC POLYAMINE DERIVATE AS FIXING AGENT Wahyu Fajar Winata; Dwi Ari Setyorini; Nur Mutia Rosiati; Fauzi Ashari
Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit Vol. 23 No. 1 (2024): Berkala Penelitian Kulit, Sepatu, dan Produk Kulit
Publisher : Politek ATK Yogyakarta Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58533/rdyhkr82

Abstract

This research aims to improve the color fastness of sheep Cabrera golf gloves during the post-tanning process. The post-tanning process includes aging, sammying, shaving, wetting back, re-tanning I, neutralization I, surface dyeing, fixation I, top dyeing, fixation II, neutralization II, fatliquoring, and top fatliquoring. Fastness skin color can be repaired by reprocessing the dyeing process. The raw material used is three sheets of crust-dyed sheep cabretta article of reject quality with a thickness of 0.5-0.55 mm. The chemicals used in the research were H₂O, Foryl PKN, Ammonia, Nexopol AM, Nexopol LA, Formic Acid (FA), Busan 30WB, and Dermafix P Liquid. The post-tanning process using FC fixing material produces crust-dyed sheep cabretta articles with a high color fading, and the finished leather has low rubbing resistance. The test results on crust-dyed skin samples showed that the fading that occurred was very high in the sweat solution, indicated by the solution's color following the sample's color. Reprocessing using Dermafix P Liquid reduced color fading in the sweat solution. On finished leather, dry and wet rubbing resistance was increased to a value of 5 for dry rubbing and a value of 4 for wet rubbing after reprocessing using Dermafix P Liquid, where previously the dry fastness value was 3, and the damp fastness value was 2 in the initial sample. Based on the results obtained, it can be concluded that reprocessing by replacing fixation materials and adding other necessary ingredients can produce leather of better quality and by SNI standards.
THE EFFECT OF DIFFERENT PRETANNING INGREDIENTS ON QUALITY OF THE SKIN OF TILAPIA FISH(OREOCHROMIS NILOTICUS) TANNED OF GAMBIER (UNCARIA GAMBIER) Heru Susanto; Swatika Juhana; Fadzkurisma Robbika; Fauzi Ashari; Wahyu Fajar Winata
Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit Vol. 23 No. 2 (2024): Berkala Penelitian Kulit, Sepatu, dan Produk Kulit
Publisher : Politek ATK Yogyakarta Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58533/y2sngz53

Abstract

Tanning of tilapia fish skin (Oreochromis niloticus) has been carried out using a variety of pretanning materials such as aluminum, chrome, glutaraldehyde, syntan with gambier (Uncaria gambier) as the main tanning agent. The research aims to determine the effect of pretanning ingredients on the physical and chemical quality of the skin tilapia fish of gambir so that the best formulation can be obtained. The process of tanning tilapia skin is carried out conventionally from salt-cured tilapia skin processed by BHO to the pikling process, pretanning with a variety of pretanning materials chrome, aluminum, glutaraldehyde and SB sodatan at 4% each, followed by main tanning with gambier various (25% 30%, 35%), post tanning, and finishing. The results of the skin quality test of tilapia fish tanned gambier with the best formula, namely code L with SB 4% sodatan pretanning with 35% gambier. This optimum formula produces a shrinkage temperature of 70 oC, higher tensile strength, sewing strength and burst resistance, the highest bound tannin content is 30.87%, and the degree of tanning is 69.18%.
EFFICIENCY OF WATER AND CHROME USE IN CABRETTA SHEEP TANNING PROCESS USING EXHAUSTED TANNING CHROME METHOD Akbar Izzulhaq; Mustafidah Udkhiyati; Wahyu Fajar Winata
Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit Vol. 21 No. 2 (2022): Berkala Penelitian Kulit, Sepatu dan Produk Kulit
Publisher : Politek ATK Yogyakarta Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58533/mk0rvw05

Abstract

This study aims to make chromium and water more efficient in the tanning process. The methods used include water efficiency from 100% to 50% and chromium reduction from 6% to 4% using exhausted chrome tanning method. The raw material used is grade 6 pikel sheepskin and the auxiliary chemical used is acrylic copolymer. The tests carried out were organoleptic, physical and chromium content in the waste. Organoleptic and physical tests showed that the condition of slackness, and the suitability of color on the crust of the pearl white cabretta article had met consumer purchasing standards. In the results of physical testing of samples using the exhausted chrome tanning method, almost all of them meet the test standards from SII-0943-84. Waste testing showed that the use of the efficiency method had a significant decrease in the amount of total chromium, from 757.35 mg/L to 487.80 mg/L.
THE EFFECT OF MOLASSES AS AN ADHESIVE MATERIAL FOR MAKING ENVIRONMENTALLY FRIENDLY LIVESTOCK PELLETS wahyu fajar winata; Hafitz Noprianto Ramadhan; Dimas Betran Saputra
Berkala Penelitian Teknologi Kulit, Sepatu, dan Produk Kulit Vol. 24 No. 2 (2025): Berkala Penelitian Kulit, Sepatu, dan Produk Kulit
Publisher : Politek ATK Yogyakarta Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58533/j18yvr80

Abstract

This study aims to determine the effect of using molasses and starch adhesives on the physical quality of pellets made from fleshing waste generated by the leather tanning industry. The research employed a Completely Randomized Design (CRD) with three treatments: no adhesive (P0), addition of 2.5% molasses (P1), and addition of 2.5% starch (P2), each with three replications. The observed parameters included the physical characteristics of the pellets (color, texture, aroma, and compactness) as well as their reaction response to HCl solution. The results showed that the addition of adhesives significantly improved pellet quality. Treatment P1 produced the most compact, dense, and stable pellets, with a more intense reaction to HCl, while P2 provided moderate improvements and remained superior to P0. Pellets without adhesive (P0) had a loose structure, were less compact, and easily crumbled. Therefore, molasses is identified as the most effective adhesive for improving the physical quality and stability of pellets made from fleshing waste, whereas starch can serve as an alternative adhesive with lower effectiveness.
Co-Authors Akbar Izzulhaq Dewi, Zahra Saadiya Dimas Betran Saputra Dwi Ari Setyorini Elis Nurbalia Fadzkurisma Robbika Fauzi Ashari Fauzi Ashari Fauzi Ashari Fauzi Ashari Hafitz Noprianto Ramadhan Heru Susanto Himawan Santoso Himawan Santoso Ika Yanti Ika Yanti, Ika Laili Rachmawati Mustafidah Udkhiyati Nabilla Indrakusuma Nais Pinta Adetya Nur Mutia Rosiati Nur Mutia Rosiati Nuraini, Eko Prakoso, Muhammad Ridwan Prasetyo Hermawan Prasetyo Hermawan Rahmayani, Elyka Rina Dwi Asmarani SUGIYANTO Swatika Juhana Tiyastuti, Rini