A B S T R A C TMango peel waste which has a carbon functional group was converted to activated carbon. The as-synthesized activated carbon (AC) was then utilized as an adsorbent for batik waste which contains heavy metal substances such as Fe2+. The purpose of this study was to determine the optimum process variation in absorbing heavy metal ion Fe contained in batik waste. Four variation methods of activated carbon synthesis were explored to determine the most suitable method of AC synthesis. The results showed that the sample synthesized using a combination physical-chemical-physical process was the best process variation resulting in percentage removal of Fe2+ of 84.81%. FTIR showed that the functional groups in mango peel were visible for all variations of the process, namely hydroxyl (-OH) derived from cellulose and hemicellulose and carboxyl (-COOH) derived from pectin. The adsorption study showed that the most suitable isotherm for all process variations was Langmuir with an R2 value of 0.9999 for the MPAC-4 sample. The adsorption mechanism is physisorption with a value of E < 8 kJ/mol based on the D-R isotherm and has the largest adsorption capacity of Qmax 8.2 mg/g.Keywords: batik waste; adsorption; activated carbon; iron waste; mango peelABSTRAKLimbah kulit mangga yang memiliki gugus fungsi karbon dapat dikonversi menjadi karbon aktif. Karbon aktif hasil sintesis (AC) tersebut selanjutnya dimanfaatkan sebagai adsorben limbah batik yang mengandung zat logam berat seperti Fe2+. Tujuan dari penelitian ini adalah untuk mengetahui variasi proses optimum dalam menyerap ion logam berat Fe yang terkandung dalam limbah batik. Terdapat 4 variasi metode sintesis karbon aktif yang diteliti untuk menentukan metode sintesis AC yang paling cocok. Hasil penelitian menunjukkan bahwa sampel yang disintesis menggunakan kombinasi proses fisika-kimia-fisika merupakan variasi proses terbaik dengan persentase penyisihan Fe2+ sebesar 84,81%. Analisis FTIR menunjukkan bahwa gugus fungsi pada kulit mangga terlihat untuk semua variasi proses, yaitu hidroksil (-OH) yang berasal dari selulosa dan hemiselulosa dan karboksil (-COOH) yang berasal dari pektin. Studi adsorpsi menunjukkan bahwa isoterm yang paling cocok untuk semua variasi proses adalah Langmuir dengan nilai R2 = 0,9999 untuk sampel MPAC-4. Mekanisme adsorpsi adalah fisisorpsi dengan nilai E < 8 kJ/mol berdasarkan isoterm DR dan memiliki kapasitas adsorpsi terbesar Qmax 8,2 mg/g.Kata kunci: limbah batik; adsorpsi; karbon aktif; limbah besi; kulit mangga

Mango leaf extract has proven to contain flavonoids that serve as antioxidants. In this study, a comparison between traditional maceration and sonication on flavonoid extraction from mango leaf was investigated. The various ratios of ethanol and acetone were utilized as solvents (1:5, 1:10, and 1:15). The sonication process, which uses an ultrasonic cleaning bath set at 40 oC, takes 30 minutes as contrasted to the maceration procedure of 36 hours treatment at room temperature. The flavonoid test using aluminum (III) chloride (AlCl3) colorimetric technique shows that acetone provides greater solvent power than ethanol. According to this study, the optimal ratios for the maceration and sonication procedures are 1:10 and 1:15, respectively. The maceration process resulted in the optimum extract of 0.186 mgQE/g dry leaves. Meanwhile, using a 1:15 acetone solvent ratio and the sonication method, the highest concentration of flavonoid components was discovered, reaching 0.143 mgQE/g dry material with 54 times shorter time.

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A series of analyses techniques were performed to study the influence of different acid concentrations on the rock properties during the acidizing process. Based on the Thin section and Routine Core Analysis (RCA), the calcite content have effect on the reservoir quality from the aspect of rock-fluid properties. In this paper, the physical and mineralogical responses to rock acidizing of carbonate rock are evaluated. This study found that calcite content decreases approximately 25% from the total calcite content of rock samples after the addition of HCl. Scanning Electron Microscope (SEM) Analysis show that samples treated using HCl 15% provide a wider pore size distribution, resulting in the increasing permeability fluid flow rate

Chemical reduction with sodium thiosulfate is commonly used to dechlorinate chlorinated waste. U.S. Environmental Protection Agency recommends sodium thiosulfate (Na2S2O3) as a dechlorinating agent for waste samples containing residual chlorine before being released into the environment or entering the distribution system. However, sodium thiosulfate's efficiency and chlorination kinetics at different concentrations are still unknown due to a lack of information on chlorination kinetics. The study was conducted by determining the number of efficient doses of sodium thiosulfate and observing chlorination kinetics using sodium thiosulfate as a dechlorination agent observed at different stoichiometric ratios (1x, 1.5x, and 2x). Sodium thiosulfate at a stoichiometric dose of 2x can reduce chlorine residue by up to 0.4 ppm. The regression analysis of and constant rate are used in the kinetic analysis of sodium thiosulfate dechlorination processes. The kinetics of the chlorination process employing sodium thiosulfate is first order to the total concentration of chlorine in solution at a stoichiometric dosage of 2x, according to the findings.