Recovery Perak Nitrat dari senyawa Perak dalam Limbah Fotografi dengan metoda Adsorpsi-Desorpsi

LESTARI, Eva, Dr. Sri Juari Santosa, M.Eng

2005 | Tesis | S2 Ilmu Kimia

Telah dilakukan recovery perak nitrat dari senyawa perak dalam limbah fotografi dengan metoda adsorpsi menggunakan adsorben kitin (C) dan asam humat diimobilisasikan pada kitin (HAC) dan dilanjutkan dengan desorpsi menggunakan HNO3 0,1 M. Beberapa parameter adsorpsi seperti laju, energi, kapasitas serta kondisi keasaman optimum adsorpsi ditentukan. Dipelajari pula pengaruh suhu pemanasan untuk meningkatkan keefektifan proses recovery. Penelitian diawali dengan isolasi asam humat dari tanah gambut dan kitin dari cangkang kepiting, imobilisasi asam humat pada kitin dan karakterisasi adsorben C dan HAC. Kondisi optimum adsorpsi dipelajari melalui interaksi senyawa perak dalam limbah fotografi dengan adsorben pada variasi pH dari 2 sampai 10. Laju adsorpsi dipelajari melalui interaksi senyawa perak dalam limbah fotografi dengan adsorben pada variasi waktu dari 2 sampai 120 menit. Energi dan kapasitas adsorpsi dipelajari melalui interaksi adsorben dengan senyawa perak dalam limbah fotografi yang diencerkan dengan faktor pengenceran 55x, 60x, 65x, 70x dan 75x, dan masing-masing seri larutan dikondisikan pada tiga suhu adsorpsi yang berbeda yaitu 30, 40 dan 50oC. Hasil penelitian menunjukkan bahwa pH 2 merupakan keasaman terbaik adsorpsi senyawa perak dalam limbah fotografi pada adsorben C dan HAC. Adsorpsi senyawa perak pada adsorben C dan HAC dapat dibedakan menjadi adsorpsi lambat dan cepat. Konstanta laju orde satu (k) untuk adsorpsi lambat pada adsorben C dan HAC masing-masing adalah 0,0024 dan 0,0014 menit-1, sedangkan harga k untuk adsorpsi cepat masing-masing adalah 0,0054 dan 0,0119 menit-1. Dari suhu 30 ke 50oC, kapasitas adsorpsi cenderung naik yaitu dari 1,90.10-5 menjadi 2,28.10-5 mol/g untuk adsorben C, dan dari 1,93.10-5 menjadi 2,22.10-5 mol/g untuk adsorben HAC, sedangkan energi adsorpsi pada kedua adsorben pada kisaran suhu tersebut berharga sekitar 37 kJ/mol. Dengan diawali pemanasan pada suhu 90oC selama 40 menit, senyawa perak yang teradsorpsi dari limbah fotografi pada adsorben C dan HAC masing-masing sebesar 68,99 dan 70,92%. Desorpsi dengan HNO3 0,1 M selama 2 jam, senyawa perak yang terdesorpsi atau terecovery dari adsorben C dan HAC berturut-turut sebesar 22,99 dan 24,18%.

It had been done a recovery of silver nitrate from silver compounds in photography wastewater by adsorption method using chitin (C) and immobilized humic acid on chitin (HAC) adsorbents and followed by desorption with HNO3 0.1 M. Several adsorption parameters such as rate, energy, capacity and optimum acidity condition of adsorption were determined. To increase the effectivity of recovery, the effect of temperature was also investigated. This work was started with isolation of humic acid from peat soil and chitin from crab shell, immobilization of humic acid on chitin, and characterization of adsorbents of C and HAC. Optimum condition was studied by interacting the adsorbents with silver compounds in photography wastewater on various of pH from 2 to 10. Adsorption rate was studied by interacting the silver compounds in the photography wastewater with adsorbent on various time from 2 to 120 minutes. The determination of the energy and the capacity of adsorption were studied by interacting the adsorbent with silver compounds in the photography wastewater on various initial concentration prepared by dilution of the wastewater with dilution factor of 55, 60, 65, 70, and 75 times, and these solution series were then conditioned in three different temperatures, i.e. 30, 40, and 50oC. The result showed that pH 2 was the optimum acidity for the adsorption of silver compounds in photography wastewater on both C and HAC adsorbents. Adsorption of silver compounds on C and HAC adsorbents can be differentiated into slow and fast adsorptions. First order rate constants (k) for slow adsorption on C and HAC adsorbents were 0.0024 and 0.0014 minute-1, and those for the fast adsorption were 0.0054 and 0.0119 minute-1, respectively. From adsorption temperature 30 to 50°C, adsorption capacities moved from 1.90 x 10-5 to 2.28 x 10-5 mole/g for C, and from 1.93 x 10-5 to 2.22 x 10-5 mole/g for HAC adsorbents, while adsorption energies of both adsorbents at this temperature range were close to 37 kJ/mole. With initial heating at a temperature of 90oC during 40 minutes, silver compounds from photography wastewater that was adsorbed on C and HAC adsorbents were 68.99 and 70.92%, respectively. Desorption with HNO3 0.1 M for as long as 2 hours, recovery of silver compounds from C and HAC adsorbents were 22.99 and 24.18%, respectively

Kata Kunci : Adsorpsi,Desorpsi,Limbah Fotografi,Perak Nitrat, silver, silver nitrate, photography wastewater, adsorption, desorption