Karakteristik adsorpsi Cr(III) dengan adsorben kitin dan humat kitin dalam sistem Fluidized Bed

JUMADI, Dr. Sri Juari Santosa, M.Eng

2006 | Tesis | S2 Ilmu Kimia

Telah dilakukan preparasi dua adsorben yaitu adsorben kitin dan kitin yang diimobilisasi dengan asam humat (humat-kitin) untuk adsorpsi Cr2(SO4)3 limbah cair industri penyamakan kulit dengan menggunakan sistem fluidized bed. Dengan mengatur besarnya laju alir dalam sistem fluidized bed maka dapat ditentukan besarnya waktu maksimum adsorpsi dan desorpsi, koefisien transfer massa (Kca) pada proses adsorpsi dan desorpsi serta prosentase recovery. Penelitian diawali dengan isolasi asam humat dari tanah gambut Kalimantan dan kitin dari cangkang kepiting asal Semarang serta dilakukan imobilisasi asam humat pada kitin. Kondisi optimum adsorpsi dilakukan melalui interaksi Cr2(SO4)3 limbah model dan limbah cair industri penyamakan kulit dengan adsorben pada pH 4,1. Waktu Adsorpsi dipelajari melalui interaksi Cr2(SO4)3 pada adsorben dengan variasi waktu antara 1 sampai 150 menit . Proses desorpsi menggunakan larutan H2SO4 0,1 M dengan variasi waktu antara 1 sampai 150 menit. Proses adsorpsi dan desorpsi dilakukan dengan laju alir 60, 90, dan 110 ml.menit-1 melalui sistem fluidized bed. Hasil penelitian adsorpsi Cr2(SO4)3 dalam larutan reference dan limbah cair industri penyamakan kulit dengan adsorben kitin dan humat kitin menunjukan bahwa jika laju alir diperbesar, ternyata waktu maksimum adsorpsi semakin menurun sedangkan waktu maksimum desorpsi cenderung naik. Pada laju alir yang sama ternyata waktu maksimum adsorpsi dan desorpsi untuk adsorben humat kitin lebih kecil dibandingkan adsorben kitin. Demikian juga, kenaikan laju alir akan diikuti dengan kenaikan jumlah maksimum krom yang teradsorpsi dan terdesorpsi. Sedangkan besarnya harga Kca proses adsorpsi dan Kca proses desorpsi dari larutan reference dan limbah cair industri penyamakan kulit untuk adsorben kitin dan adsorben humat kitin mengikuti keteraturan sebagai berikut yaitu semakin besar laju alir ternyata harga Kca proses adsorpsi semakin besar dan Kca proses desorpsi semakin kecil. Adapaun besarnya prosentase recovery krom dari larutan reference dan limbah cair industri penyamakan kulit untuk adsorben kitin berturut-turut sebesar 97%; 96%; 95% dan 93%; 96%; 95% serta 98%; 96%; 96% dan 95%; 97%; 96% untuk adsorben humat kitin.

Two adsorbent chitin and immobilized chitin by humic acid (humatechitin) have been prepared for the adsorption of Cr2(SO4)3 of wastewater of tanning industry by using fluidized bed system. Flowrate of the wastewater in the fluidized bed system can be adjusted to enable us to determine the maximum time of adsorption and desorption, the coefficient of mass transfer (Kca) of the adsorption-desorption process and the procentage of recovery. This research was started with the isolation of humic acid from the peaty soil of Kalimantan and chitin from crab shell originated from the farm in Semarang. Part of the chitin was immobilized with the above mentioned humic acid. Optimum condition of adsorption was created by the interaction of Cr2(SO4)3 of reference solution Cr(III) and that of the wastewater of tanning industry obtained through the adsorbent in an environment of acidity of pH 4,1. Duration of adsorption through the interaction of Cr2(SO4)3 the adsorbent varied between 1 to 150 minute and the duration of desorption process using H2SO4 0,1M solution varied between 1 to 150 minute. These adsorption and desorption processes were done in the fluidized bed with flowrate 60, 90, and 110 ml/min. The result of this research shows that increasing the flowrate of the wastewater in the fluidized bed decreases the maximum time of adsorption but increases the maximum time of desorption. This research also shows that at the same flowrate maximum adsorption time of adsorbent humate-chitin is less than that of adsorbent chitin and the increase in flowrate increases the maximum quantity of chromium adsorbed and desorbed. The value Kca of the adsorption process of the reference solution and wastewater of the tanning industry for chitin and humate-chitin adsorbents are in accordance with the following rule i.e: the higher the flowrate the higher the value of Kca of adsorption process but the lower the value of Kca of desorption process. The value of the procentage of chromium recovery from the reference solution and the wastewater of the tanning industry with chitin adsorbent are respectively 97%, 96%, 95% and 93%, 96%, 95% while for humate-chitin adsorbent 98%, 96%, 96% and 95%, 97%, 98%.

Kata Kunci : Adsorpsi Cr2(SO4)3,Limbah Cair,Fluidized Bed, wastewater of the tanning industry, reference solution , chitin, humate-chitin, adsorption, desorption, fluidized bed