No abstract

Abstract. Precipitated silica from silica and carbon dioxide gas has been studied successfully. The source of silica was obtained from pumice stone while precipitation process was carried out with carbon dioxide gas (CO 2 ). The sodium silicate solution was obtained by extracting the silica from pumice stone with sodium hydroxide (NaOH) solution and heated to 100 °C for 1 h. The carbon dioxide gas is injected into the aqueous solution of sodium silicate in a bubble column reactor to form precipitated silica. m 2 /g. The results indicate that the products obtained are precipitate silica have surface area in the range of 100 -227 m 2 /g, silica concentration more than 80%, white in appearance, and silica concentration reached 90% at pH 7.

The precipitated silica prepared by reaction of sodium silicate and gas CO2 on fixed bed column have been production successfully. In this study, silica from bagasse was extraction by sodium hydroxide 2N solution to produce sodium silicate solution. The sodium silicate solution was dilute by demineralize water to produce some concentration in the range of 0.33-0.98 %SiO2. Fixed bed column has a diameter of 7.5 cm with a height of 50 cm and a pH control apparatus. CO2 gas and sodium silicate liquid are both flowed from under of the column with a specified flow rate. The precipitate process was carried out on a fixed bed column with high of bed in the range of 10-30 cm. The effect of silica concentration and the high of the bed on the characterize of the precipitated silica product have been studied. The precipitated silica product characterized by XRF, XRD, SEM-EDX and BET. The quality of precipitated silica produced in the range concentration of 95-98 w% SiO2, surface area (BET) in the range of 46.1 – 58.8 m2/g.

<p>Tofu waste is gotten after processing soybean, and this waste contains a lot of polluting substances, hence it can pollute rivers and cause health problems. Meanwhile, one method used for treating wastewater into clean water is called the jartest method and its processes include coagulation-flocculation and deposition. This study aims to determine the effectiveness of green mussel shells as coagulants in the treatment of tofu industrial liquid waste. The variables used were 100 mesh green mussel shell powder, 1000 mL of liquid tofu dregs, 150 rpm fast stirring speed for 2 minutes, and 60 rpm slow stirring speed for 15 minutes. Furthermore, chitosan was used with different weight variations in grams (0.5, 0.7, 0.9, 1.1, and 1.3) as well as precipitation time with variations in minutes (20, 30, 40, 50, and 60). The content of Chitosan water was 1.29% and its degree of deacetylation was 65.04%. The result of the preliminary analysis of tofu liquid waste with a coagulant showed BOD, COD, and TSS levels of 965.25mg/L, 435mg/L, and 395mg/L with pH 4 respectively. However, these levels were changed to 195.56mg / L; 299mg/L; and 195.32 mg/L with pH 6 after the final analysis of the liquid waste was conducted.</p>

Merebaknya wabah pandemi Covid-19 yang telah menyebar di beberapa negara termasuk Indonesia mengalami peningkatan baik dalam jumlah kasus ataupun korban jiwa. Salah satu cara untuk menghindar dari virus Covid-19 adalah dengan menjaga imun atau daya tahan tubuh. Indonesia merupakan negara agraris yang kaya akan hasil pertanian salah satunya adalah rempah-rempah yang merupakan bahan herbal bisa digunakan untuk menjaga daya tahan tubuh. Tanaman herbal banyak mengandung senyawa bioaktif yang memiliki barbagai manfaat bagi kehidupan manusia diantaranya sebagai sumber antioksidan, antibakteri, antiinflamasi dan anti kanker. Komposisi dan proses yang tepat serta disesuaikan dengan kebutuhan tubuh akan dapat menjaga daya tahan tubuh dalam masa Pandemi Covid-19.