Kegiatan industri di Kalimantan lebih dari 70% merupakan industri pertambangan batu bara. Limbah hasil kegiatan pertambangan dapat menyebabkan pencemaran air yang mengakibatkan turunnya kualitas air akibat kandungan air limbah tambang yang mengandung logam berat terlarut dengan sifat asam yang tinggi. Oleh sebab itu diperlukan adanya pengujian kadar besi pada air limbah tambang sebagai upaya pengendalian pencemaran air agar sesuai dengan baku mutu air limbah pertambangan. Pengambilan contoh sampel uji air limbah berdasarkan SNI 6989.59-2008 yaitu sampel air limbah diambil dari tiga titik lokasi kolam penataan area stockpile pada industri pertambangan batu bara di Kabupaten Sangatta, Kalimantan Timur. Validasi setiap parameter uji dilakukan di Laboratorium Terpadu ITK  dengan pengulangan untuk masing-masing sampel uji sebanyak 7 (tujuh) kali pengulangan. Pada parameter validasi metode analisis untuk uji linearitas pada air limbah diperoleh nilai koefisien korelasi regresi linier (r) sebesar 0,999; batas deteksi dan batas kuantitasi diperoleh sebesar 0,141 mg/L dan 0,470 mg/L. Pada uji presisi sampel uji air limbah tambang A, B dan C didapatkan nilai %RSDr sebesar 1,602%; 0,829% dan 0,782%. Nilai %recovery pada masing-masing air limbah adalah 103,429%, 108,870% dan 95,116%. Hasil pengujian kadar besi (Fe) menggunakan spektrofotometer UV-Vis dengan pengompleks tiosianat (KSCN) pada limbah A, B dan C adalah 0,721 mg/L, 2,786 mg/L dan 4,961 mg/L. Hasil tersebut menunjukkan bahwa kadar besi sampel air limbah tidak melebihi batas ambang air limbah pertambangan.

Teknik pembalutan luka saat ini menerapkan metode perawatan luka modern dengan cara mempertahankan isolasi lingkungan luka dalam keadaan tertutup dan lembab. Ada beberapa jenis pembalut luka yang telah dikembangkan, salah satunya hidrogel. Hidrogel merupakan pembalut luka berbentuk lembaran yang memiliki kemampuan menyerap cairan luka dan memiliki stabilitas yang baik pada pH asam sehingga dapat digunakan untuk pengobatan luka bakar. Dalam penelitian ini, hidrogel dibuat menggunakan polimer alami seperti pektin dan gelatin. Kedua bahan tersebut dikombinasikan menggunakan metode ikatan silang dengan penambahan asam sitrat sebagai agen pengikat silang. Penambahan asam sitrat memberikan pengaruh terhadap karakteristik material hidrogel yang dihasilkan, sehingga diperlukan jumlah yang tepat agar didapatkan hidrogel dengan properti material yang baik. Hidrogel juga ditambahkan zat aktif berupa flavonoid pada ekstrak kulit buah naga agar dapat digunakan sebagai pembalut luka untuk menyembuhkan luka bakar. Dari hasil penelitian, hidrogel dengan konsentrasi asam sitrat 4% (Hidrogel CA 4%) menghasilkan nilai swelling, tensile strength, dan elongation tertinggi sebesar 890%, 0,05 Mpa, dan 200%. Hasil properti mekanik dari Hidrogel CA 4% ini dibuktikan dengan uji FTIR yang telah dilakukan, yaitu munculnya gugus karbonil C=O sebagai hasil reaksi esterifikasi yang terjadi antara polimer dengan asam sitrat di daerah serapan 1733,9 cm-1.Wound dressing technique currently applies modern wound care methods by maintaining the environmental isolation of the wound in a closed and moist state. There are several types of wound dressing that have been developed, one of them is hydrogel. Hydrogel is sheet-shaped wound dressings which have the ability to absorb exudate and have good stability acidic pH that can be used for the treatment of burns. In this study, hydrogel were made using natural polymers such as pectin and gelatin. The two polymers were combined using crosslinking method with the addition of citric acid as a crosslinking agent. The addition of citric acid has affect on the characteristics of the hydrogel material produced, therefore the right amount is needed to obtain a hydrogel with good mechanical properties. Hydrogel also added by an active substance in the form of flavonoids from dragon fruit peel extract that can be used as a wound dressing to cure burns. This study resulting hydrogel with a concentration of 4% citric acid (Hydrogel CA 4%) produced highest value of swelling, tensile strength, and elongation are 890%, 0.05 Mpa, and 200%, repectively. The mechanical properties of Hydrogel CA 4% was proved by FTIR test that had been carried out, namely the presence of C=O carbonyl group as a result of the esterification reaction that occurred between the polymers and citric acid in the absorption area of 1733.9 cm-1.

No abstract

No abstract

Postharvest treatment is one of the important factors that affected the shelf-life of fresh-cut pineapples (Ananas comosus). Pineapples have a short shelf life, that is 2-3 days after harvest without cold storage. Recently, the application of edible coatings is widely used to extend the shelf-life of pineapples. The edible coating can be produced from alginate, starch, chitosan, or aloe vera as the main composition. In this study, it is purposed to prolonged the storability of pineapples using starch-based edible coating combined with chitosan. Starch is obtained from cassava peels because they contain 44-59% of starch. On the other hand, chitosan acts as a stabilizer and antimicrobial agent. Furthermore, glycerol is added as a plasticizer in order to increase the elasticity of the edible film. The edible coating was prepared using various compositions of starch and glycerol (in % w/v), then 1% w/v of chitosan dissolved in ascorbic acid was added to the solution. The fresh-cut pineapples were dip-coated into the mixture. Subsequently, they were stored in the refrigerator at 12°C. Physicochemical properties of cassava peels starch-based edible coating were examined by functional groups analysis, solubility analysis, and pH measurement. The results showed that chitosan-modified edible coating with 5 % w/v of starch-0.6 ml/gr of glycerol can prolong the shelf-life of pineapples to 14 days. It had 58.46% solubility and 18% of increasing pH within 14 days. In addition, this variable obtained the highest score of overall acceptance in organoleptic evaluation, which was 5.47 out of 7.