Coffee bean husks waste contains chemical compounds such as tannins and flavonoids. These compounds are known to inhibit corrosion. Corrosion inhibition of mild steel in 0.75 M H2SO4 has been investigated using the presence and absence of coffee bean husk extract (CBHE). The effect of inhibition efficiency and corrosion rate on extract concentration and immersion duration was studied using the method of weight loss. The inhibition efficiency increases and the corrosion rate decreases with increasing immersion time and the concentration of CBHE. The corrosion inhibition efficiency was obtained 97.54 % obtained at 72 hours immersion and addition of CBHE 10 g/L. Steel surface adsorption was examined by SEM and FTIR spectroscopy. CBHE is recommended as a good inhibitor.

The Shorea sumatrana (tengkawang) plant is endemic to Indonesia, especially in Kalimantan and Sumatera regions, which produces chemical diversity especially as a natural drugs. Specific aims to investigate both the profile analysis of fatty acid and antibacterial potential of tengkawang oil. The extract of tengkawang oil was carried out using the soxhlet extraction method. The profile analysis of fatty acid was verified by GC-MS and the antibacterial activity was evaluated using disc-diffusion method. The profile analysis of fatty acid of tengkawang oil indicated the presence of palmitic acid (17.26%), stearic acid (60.68%), oleic acid (11.98%), oleic acid chloride (1.80%), stearic acid chloride (1.86%), glycidyl stearate (1.92%), diethyl phthalate (4%), and 2-monopalmitin (0.5%). We determined the antibacterial activity by the diameter of inhibition of growth zone against Salmonella enteritidis, Escherichia coli, Staphylococcus aureus, and Bacillus cereus at a concentration of 12.5%, 25%, 50%. These were compared with standard tetracycline as positive control and DMSO was assigned negative control. It was found that the highest percentage of fatty acid in tengkawang oil is stearic acid, at 60.68%, and that tengkawang oil is an antibacterial agent with a concentration optimum at 25% with more susceptibility to Gram-positive than Gram-negative bacteria.

Timbal merupakan salah satu polutan yang paling banyak digunakan dalam beberapa kegiatan industri seperti penambangan, peleburan, pemurnian minyak bumi, percetakan, produksi pigmen, dan pembuatan baterai.  Permasalahan logam berat dapat ditanggulangi dengan penurunan kadar logam berat menggunakan teknik penyerapan. Salah satu adsorben yang digunakan untuk penyerapan ion Pb(II) adalah limbah padat lumpur aktif  dari pengolahan air minum. Penelitian ini bertujuan untuk menggunakan limbah padat lumpur aktif yang di ambil dari sisa pengolahan air minum PDAM Tirta Mayang Jambi dan diaktifasi menggunakan KOH. Adsorben digunakan untuk penyerapan ion Pb(II) dengan metoda penyerapan dilakukan secara statis. Adsorben dikarakterisasi menggunakan FTIR, SEM dan XRF. Ion Pb(II) dalam larutan dianalisis dengan menggunakan metoda Spektrofotometer Serapan Atom (SSA). Parameter penyerapan yang dipelajari adalah pH diperoleh pada pH 5, massa adsorben 0,2 g, waktu kontak 45 menit dan konsentrasi ion Pb(II) adalah 300 mg/L dengan kapasitas adsorbs 25,42 mg/g.ABSTRACT The lead metal is one of the pollutants most widely used in several industrial activities such as mining, smelting, refining petroleum, printing, pigment production, and battery production. Heavy metal problems can be overcome by decreasing heavy metal content using adsorption techniques. One of the adsorbents used for Pb(II) ion adsorption is avtivated sludge solid waste from drinking water treatment. This study aims using activated sludge solid waste from drinking water treatment Local Water Company Tirta Mayang Jambi and activated using KOH. The adsorbent used for adsorption of Pb(II) ion by  batch technique. Adsorbents are characterized using FTIR. SEM, XRF.  Pb(II) ion in the solution analysis with Adsorption Atomic Spectrophotometer (AAS). The adsorption parameters studied were pH was pH 5, adsorbent mass was 0.2 g, contact time was 45 minute and concentration of Pb(II) ion was 300 mg/L with adsorption capacity was 25.42 mg/g.

No abstract

Indonesia is the largest palm plantation that reaches 32 million tonnes palm oil production per year with 84 million tones Palm Oil Mill Effluent (POME) as liquid waste. POME contains many organic substances. The quality of POME for its utilization is generally measured in COD which has range 30000 -100.000 ppm. Microbial convertion for biogas especially for bio-H2 enrichment, the active sludge was pretreated physically to suppress methanogenesis microbes. H2 Biogas production was conducted at pH 5-6. Additional 10% phosphate buffer was done in the beginning only. The production of H2 biogas was influenced by hydrostatic pressure in closed batch system. Inoculumsmedium ratio also influenced the H2 biogas productivity, reached 0.7 ml/ml POME with more than 50% H2. Scaling up anaerobic in 2.5 L working volume bioreactor, H2 biogas productivity reached 0.86 ml/ml POME by 10% inoculums because of no hydrostatic pressure. In bio-reactor, H2-CO2 in H2 biogas was affected by the amount of active sludge. In the beginning of H2 biogas, H2 reached 80%. However, at subsequence process, fed batch, with retention time 2.5 day and 3 days H2 biogas production, the active sludge was accumulated and caused the decreasing H2, finally only 46% at the 3rd day. The consortium tended to produce more CO2 as the result of primary metabolite rather than H2. Raising inoculums to level 15% improved productivity only in the beginning but H2 content was getting less, only 59%. Additional feeding would cause more accumulation sludge and more decreasing H2 content to 31% on the 3rd day. Thus, the ratio of active sludge and substrate availability must be controlled to gain optimum H2. Limited substrate will cause the direction of bio-conversion more in CO2 rather than H2.