JURNAL KIMIA SAINTEK DAN PENDIDIKAN

UNJUK KERJA NaOH DALAM MEREDUKSI LOGAM BERAT PADA LIMBAH ABU BOILER

Maria Peratenta Sembiring — 2024-06-10

Proses pembakaran batu bara menghasilkan emisi berupa gas SO₂, NO₂, CO, CO₂, volatile hydrocarbon (VHC), suspended particulate matter (SPM), serta residu padat berupa abu boiler. Abu boiler mengandung berbagai logam berat beracun, diantaranya tembaga (Cu), kobalt (Co), kromium (Cr), cadmium (Cd) dan timbal (Pb). Penelitian ini bertujuan untuk menentukan efisiensi reduksi logam berat Cu, Co, Cr, Pb, dan total dengan melakukan ekstraksi menggunakan pelarut kimia NaOH dan mengubah logam transisi menjadi kompleks dengan Ethylene diamine tetraacetic acid (EDTA) pada rasio EDTA: abu boiler sebesar 1:2, 1:1, 2:1; durasi pengadukan sebesar 2 dan 4 jam; serta suhu ekstraksi sebesar 25 dan 60 ^oC. Analisis Inductively Coupled Plasma (ICP) dilakukan untuk mengetahui penurunan kadar logam berat dari ekstrak abu boiler. Hasil penelitian menunjukkan bahwa kondisi ekstraksi berupa rasio EDTA: abu boiler sebesar 2:1, durasi pengadukan sebesar 4 jam, dan suhu ekstraksi sebesar 60 ^oC dapat menghasilkan persentase penurunan kadar logam berat total tertinggi yang mencapai 77,2% dengan persentase penurunan kadar Co, Cr, Cu, dan Pb secara berturut-turut sebesar 75,4%, 77,9%, 74,5%, dan 81,9%. Penelitian ini diharapkan dapat menjadi rekomendasi bagi penelitian selanjutnya dalam mengeksplor potensi pemanfaatan abu boiler yaitu sebagai bahan campuran aspal, pembuatan batako, dan sebagainya.

FABRICATION AND CHARACTERIZATION OF POLYETHERSULFONE (PES) MEMBRANES BY BLENDING POLYMERS FOR REMOVAL OF ORGANIC COMPOUNDS IN AIR

Nava Resi Br Sembiring — 2024-06-10

The PES membrane was modified using a polymer blending method to improve the performance and characteristics of the membrane. This research aims to see the effect of adding biosilica additives on the performance characteristics of PES membranes and determine the optimal composition of additives and solvents for making membranes. The membrane was made using the Non-solvent Induced Phase Separation (NIPS) method with a composition consisting of 18% PES, with the addition of varying concentrations of silica (1%, 2%, 3%, and 4%) and the membrane using the solvent N-Methyl- 2 Pyrrolidone (NMP) and Dimethyl Sulfoxide (DMSO). Membrane characterization was carried out by observing membrane morphology using Scanning Electron Microscopy (SEM), membrane surface functional group analysis test using Fourier Tranform Infrared (FTIR), membrane porosity test using the dry-wet weight procedure method, the highest porosity value was found on membrane B2 using a solvent DMSO with 2% silica is 16.88%. Membrane performance was carried out by pure water flux testing, the highest pure water flux value was found in membrane B2 with 2% silica, namely 64.14 L/m2.h. The antifouling test uses flux ratio recovery, the highest antifouling value is found on the A3 membrane with 3% silica, namely 91.3%. As well as rejection of the humic acid solution as a Natural Organic Matter (NOM) sample model using the ultrafiltration (UF) module with a dead end filtration flow system, the highest rejection value was found on the B2 membrane with 2% silica, namely 64.4%.

VERIFIKASI KUALITAS ANALISIS MANGAN MENGGUNAKAN TEKNIK ICP-OES DALAM SAMPEL AIR MINUM

Risma Sari — 2024-06-10

Drinking water quality, including the levels of dissolved metals, is an important public health consideration. Manganese (Mn) is a naturally occurring metal that can be present in drinking water sources, and excessive intake of Mn can have adverse health effects. The objective of this study was to verify the performance of the analytical method for the determination of manganese (Mn) concentration in drinking water samples using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) techniques at the PT XYZ Laboratory. The method verification included tests for analyte identity confirmation, linearity, precision, accuracy, as well as the determination of the Method Detection Limit (MDL) and Limit of Quantification (LOQ). The verification results showed that the ICP-OES method met the established performance requirements. The linearity test yielded a correlation coefficient (r) of 0.9998, fulfilling the criteria of r ≥ 0.995. The percent relative standard deviation (% RSD) value in the precision test was 1.41%, meeting the requirement of % RSD ≤ 2/3 % CV Horwitz. The accuracy test provided an average percent recovery of 98.66%, which is within the acceptable range of 85-120%. The determined MDL was 0.0006 mg/L, while the LOQ was 0.002 mg/L, both meeting the criteria of MDL < spiked concentration < 10 MDL and LOQ < environmental quality standard. In conclusion, the method for the determination of Mn concentration in drinking water using ICP-OES has been verified and can be used for routine analysis at the PT. XYZ Laboratory, supporting the monitoring and control of Mn levels in drinking water to ensure public health protection.

THE EFFECT OF MOLECULAR WEIGHT ON THE THERMAL STABILITY OF CELLULOSE ACETATE

Suniati Zebua — 2024-06-10

An organic ester with good mechanical characteristics (such as a high Young's modulus and tensile strength) is cellulose acetate (CA), a biobased polymer. Over the past few decades, the thermal characteristics of CA have been extensively studied. This study looked at the morphology and thermal characteristics of plasticized CA, particularly its mass loss according to thermogravimetric analysis. The analysis and comparison of the overall thermal behavior with theoretical models was done. The results of this study may have particular significance as certain polymers have a recognized dependence on β-relaxation for their mechanical attributes; this may also apply to CA.