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3 results on '"Omay Sumarna"'

1. Silver Recovery from E-Waste Printed Circuit Board Using Binary and Ternary Deep Eutectic Solvents

Author

Arrizal Abdul Aziz, Abraham Mora, Soja Siti Fatimah, Omay Sumarna, Hufaidatul Azfa Nurusyifa, Sheren Hana Elia, and Ira Kamilia Siti Huwaidah

Subjects
printed circuit board, silver metal, ternary des, glyceline des, leaching optimization, Chemistry, QD1-999
Abstract

Printed Circuit Boards (PCBs) are essential components of electronic devices containing valuable silver metal. Using sustainable methods, silver recovery from electronic trash, like PCBs, demonstrates excellent promise. This research’s objective is to determine the optimum leaching time and solid-to-liquid (S/L) ratio for extracting silver from PCB using deep eutectic solvent (DES) composed of choline chloride and glycerol (glyceline DES). The binary DES’s leaching performance was then compared to choline chloride, glycerol, and citric acid ternary systems. Fourier Transform Infrared Spectroscopy (FTIR) was carried out to analyze the bond interactions. X-ray fluorescence spectrometry (XRF) was employed to determine the PCB’s metal concentration prior to and after the leaching process. Ternary DES was viscous, colorless, stable for 60 days, and less acidic than binary DES, with a 1.21 g/mL density. FTIR peak broadening and shifting indicated the formation of a new hydrogen bond and proved a successful synthesis of ternary DES. XRF result showed that PCB’s initial silver metal content was 2.32%. The optimal silver leaching from PCB using glyceline DES was achieved after 16 hours, with a 1/20 solid-to-liquid ratio. Ternary DES demonstrated a silver leaching efficiency of 93.65%, surpassing 86.77% of glyceline. Ternary DES synthesized in this study has the potential to serve as an efficient and environmentally friendly solvent for extracting silver from PCB, providing a sustainable approach to managing electronic waste.

Published
2024
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2. Crystal Structure, Thermal Decomposition Behavior, and Order−Disorder Transition of the Guest Component of Concomitant Pseudodimorphic Clathrates between 2,2‘-Bis(9-hydroxy-9-fluorenyl)biphenyl Host and Chloroform Guest

Author

Omay Sumarna, K. M. Beketov, Edwin Weber, Jürgen Seidel, Bakhtiyar T. Ibragimov, and Wilhelm Seichter

Subjects
Biphenyl, Chloroform, Hydrogen bond, Stereochemistry, Thermal decomposition, General Chemistry, Calorimetry, Crystal structure, Condensed Matter Physics, Endothermic process, chemistry.chemical_compound, Crystallography, chemistry, General Materials Science, Powder diffraction
Abstract

Two clathrates between the 2,2‘-bis(9-hydroxy-9-fluorenyl)biphenyl host and chloroform guest, having 1:2 (α-phase) and 1:1 (β-phase) stoichiometries, have been obtained in the same vial by fast evaporation of a supersaturated solution in chloroform. The structures of the pseudodimorphs were determined by single-crystal X-ray diffraction. Their thermal properties were studied by using combined thermogravimetry-differential scanning calorimetry (TG-DSC), variable temperature X-ray powder diffraction in the temperature interval 20−250 °C, and DSC in the low-temperature interval from −140 to 20 °C. The thermal decomposition behavior of the α- and β-phase pseudodimorphs, a difference in the desolvation onset temperatures, as well as an occurrence of endothermic peaks in the low-temperature DSC curves (order−disorder transition of the guest component) have been explained on the basis of the structural data.

Published
2003

3. Formation and polymorphic phase transitions of crystalline inclusion compounds between 2,2′-bis(9-hydroxy-9-fluorenyl)biphenyl host and acetone guest

Author

K. K. Makhkamov, Kurt Köhnke, Edwin Weber, K. M. Beketov, Omay Sumarna, Bakhtiyar T. Ibragimov, and Jürgen Seidel

Subjects
Biphenyl, Organic Chemistry, Crystal structure, Calorimetry, Inclusion compound, law.invention, chemistry.chemical_compound, Crystallography, chemistry, law, Phase (matter), X-ray crystallography, Acetone, Physical and Theoretical Chemistry, Crystallization
Abstract

The 2,2′-bis(9-hydroxy-9-fluorenyl)biphenyl host compound (1) was found to form various crystalline inclusion compounds with acetone depending on the crystallization conditions or on the method of preparation (inclusion of acetone vapour, co-crystallization from solution). In order to understand and control the formation of these pseudopolymorphic phases regarding potential uses, single crystals of the existing phases (two 1:2 and one 1:1 compound) were prepared, their structures were solved by single-crystal x-ray diffraction (XRD) analysis and the desolvation and phase transformations were studied using simultaneous thermogravimetry–differential scanning calorimetry (TG–DSC) and variable-temperature powder XRD. The results explain the inclusion and desolvation behaviour and also clarify the observed, apparently accidental formation of a 1:1 or 1:2 inclusion compound at ambient temperature. Copyright © 2001 John Wiley & Sons, Ltd.

Published
2001

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