Thesis Archive
Sulfuric Acid Treated Bio-silica from Controlled Pyrolysis of Rice Husk as Adsorbent of Mercury in a Fixed Bed Column
Gueco, Benicio III
Fortades, Fortades
Tan , Gilbert
Abstract:
In the study, untreated bio-silica (UBS) and sulfuric acid treated bio-silica (SAT-BS) were evaluated for the removal of copper from synthetic wastewater. Both UBS and SAT-BS were characterized using Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR) Spectrometer. Adsorption isotherm experiment was conducted using low (150 ppm Cu, 1-5g bio-silica) and high (0.1 – 0.7 M Cu, 1g bio-silica) concentrations. Freundlich Isotherm was used at low concentration and obtained the maximum adsorption capacity of 1.0389 mg/g and 6.6349 mg/g for UBS and SAT-BS, respectively. The adsorbent’s surface area was calculated using the maximum adsorption capacity and was determined to be 0.1556 m2/g and 0.9934 m2/g for UBS and SAT-BS, respectively. Furthermore, both adsorbents were tested using fixed bed column experiment which evaluated the effects of adsorbent bed height, flowrate, and initial copper concentration in copper removal. It was observed that an increase in the adsorbent bed height from 3 cm to 9 cm showed an increase in the adsorption capacity. Effect of flowrates does not show any visible trends. Increasing initial copper concentration from 150 ppm to 350 ppm resulted in a decrease in adsorption capacity from 5.581 mg/g to 4.341 mg/g for UBS and from 1.125 mg/g to 0.656 mg/g for SAT-BS. The Bed Depth Service Time (BDST) model was evaluated to be a great fit for adsorption operating parameter prediction on the effect of adsorbent bed height with R2 > 0.91. The minimum adsorbent bed height was predicted to be 1.14 cm and 1.69 cm for UBS and SAT-BS, respectively. The Thomas model was also found to fit and predict breakthrough curves on the effect on flow rate and initial copper concentration, especially for high flow rate and high initial copper concentration. Therefore, this study shows that bio-silica from rice husk could be used as an adsorbent for copper removal in wastewater.
Adviser:
Beltran, Arnel B.