Suherman, Alex Lukmanto
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Journal : Makara Journal of Science

Optimization of Laccase Adsorption-Desorption Behaviors on Multi-Walled Carbon Nanotubes for Enzymatic Biocathodes Suherman, Alex Lukmanto; Zebda, Abdelkader; Martin, Donald K.
Makara Journal of Science Vol. 22, No. 1
Publisher : UI Scholars Hub

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Laccase adsorption-desorption behaviors on the surface of multi-walled carbon nanotubes (MWCNTs) were investi-gated using spectrophotometry and voltammetry. The optimum condition for laccase adsorption is 5.0 mg/mL of laccase in 0.01 M phosphate-buffered saline (PBS) at pH 5.0. Laccase adsorption is a reversible phenomenon that is dependent upon the nature of MWCNTs and the concentration of ionic strength in the laccase solution. Chitosan was functiona-lized as a nanoporous reservoir to minimize laccase desorption. Chitosan was found to protect approximately 97.2% of the adsorbed laccase from MWCNTs during the first six hours of observation. The three-dimensional (3D) biocathode, MWCNTs-laccase-chitosan with a 0.2 cm2 geometric area, was shown to have a stable open circuit potential (OCP) of 0.55 V, a current density of 0.33 mA cm-2 at 0.2 V vs. saturated calomel electrode (SCE), and a stable current for 20 hours of successive measurements. This report provides a new insight into the study of a high-performance laccase-based biocathode via optimization of adsorption and minimization of desorption phenomena.
Elimination of Gas and Particulate Emissions in Coal Boilers using Plasma Precipitator System Djayanti, Silvy; Suherman, Alex Lukmanto
Makara Journal of Science
Publisher : UI Scholars Hub

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A plasma precipitator reactor is an essential part of the emission treatment. This device removes fine particles, such as dust, smoke, and various toxic gases, using the force of an induced plasma charge, minimally impeding the flow of gases through the unit. In this study, the plasma precipitator combines dust deposition-capture technology by magnetic force and emission gas removal with plasma. The reactor was successfully fabricated and tested in real-world applications of the textile industry to reduce gas and particulate emissions. Using this reactor, SO2, NO2, CO, and CO2 sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), carbon dioxide (CO2) gases turned into more environmentally friendly forms, such as O2, with a decrease of approximately 91.3%, 91.4%, 88.3%, and 89.6% w/w, respectively. Meanwhile, the element and molecular forms, which contain sulfur, carbon, and nitrogen, were deposited as particulates in the electrode channels. Using this technology, the number of particulates decreased up to approximately 93.5% w/w. The plasma precipitator reactor does not require high electricity compared to (conventional) scrubbers that use a blower system. The results indicate that plasma precipitators can be used as an advanced technology to replace conventional gas and particulate emission removal systems from the industries.
Synthesis and Characterization of Cellulose Acetate Membrane from Cotton Spinning Waste Djayanti, Silvy; Kusumastuti, Syarifa Arum; Fatkhurrahman, Januar; Purwanto, Agus; Budiarto, Agung; Suherman, Alex Lukmanto
Makara Journal of Science
Publisher : UI Scholars Hub

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Cellulose acetate membrane (CAM) was successfully synthesized and characterized from the cotton spinning waste of the textile industry. The membrane was produced through the isolation, acetylation, and phase inversion stages. The highest yields of cellulose fiber and α-cellulose contents were obtained using 3.0% and 6.0% v/v NaClO, respectively. The C–O acetyl bond detected by Fourier Transform Infrared (FTIR) analysis indicates the formation of the CAM. The resulting membrane can be potentially applied as an ultrafiltration membrane for water desalination purposes in water and wastewater treatment facilities. Furthermore, the utilization of cotton spinning waste as raw material aims to produce inexpensive products and recycle solid waste from the textile industry.