Devi Ayu Nur’aini
Universitas Sultan Ageng Tirtayasa

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Analysis of Gold Concentration and Leaching Efficiency of PCB Waste Using Atomic Absorption Spectroscopy Maulina Wulansari; Yus Rama Denny M; Devi Ayu Nur’aini; Mohammad Nouvaldy
SEARCH: Science Education Research Journal Vol. 4 No. 2 (2026): SEARCH: April 2026
Publisher : IAIN Sorong

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.47945/search.v4i2.3003

Abstract

Printed circuit board (PCB) waste is a source of valuable metals with high potential for recycling, primarily because it contains relatively high concentrations of gold. This study aims to analyze the gold concentration in the filtrate obtained from leaching PCB waste using atomic absorption spectroscopy (AAS) and to evaluate the leaching efficiency achieved. The study began with sample characterization using Fire Assay and ICP-OES, followed by a pre-leaching process using 65% HNO₃ at 70°C for 60 minutes. The pre-leaching residue was then subjected to leaching using a mixture of 37% HCl and 65% HNO₃ in a 1:3 ratio at 70°C for 90 minutes. The leaching filtrate was analyzed using AAS after dilution: 1 mL of the solution was taken and diluted to 25 mL. The initial characterization results showed that the PCB sample contained 522 ppm of gold from 303.20 grams of PCB sample. AAS analysis revealed a gold concentration of 1.307 ppm in the diluted solution, equivalent to 81,69 ppm in the actual filtrate, with a leaching recovery rate of 34,44%. These results indicate that the leaching process was able to dissolve gold from the PCB matrix into the liquid phase. This study provides preliminary information on the potential for utilizing PCB waste as a source of secondary precious metals through hydrometallurgical methods and can serve as a basis for further research on leaching process optimization and gold recovery.
Analysis of Conceptual Understanding of Reaction Rate Material Using Four-Tier Multiple Choice Diagnostic Test Sandi Danar Cynthia Sari; Devi Ayu Nur’aini; Dwi Apriliyani; Laelatul Fajriyah; Siti Sa'diah; Lerisma Lehon Sinurat; Nani Resminingsih Sutisna; Triyanto Ardi
Jurnal Pendidikan Indonesia Gemilang Vol 6, No 1 (2026)
Publisher : Gemilang Maju Publikasi Ilmiah (GMPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53889/jpig.v6i1.778

Abstract

Due to the abstract nature of the concept of reaction rates, it is one of the chemistry concepts commonly misinterpreted by students. A qualitative descriptive research method was used in this study to measure students’ understanding of the concept of reaction rates and the variables involved. The population of this research consisted of 38 students from the eleventh-grade students at a Senior High School in Serang, Indonesia. A four-tier multiple-choice diagnostic test was used as the research instrument. The results showed that 13.03% understood the concept, 61.84% did not understand the concept, and 25.13% had misconceptions. The results showed that the Four-Level Multiple Choice Test is a valid instrument in uncovering misconceptions in conceptual understanding by distinguishing students who correctly answered through reasoning from students who correctly answered through guessing alone. The catalyst factor showed the highest misconceptions at 73.16%, followed by surface area at 68.95%, temperature at 53.16%, and concentration at 52.11%.