Fixed - bed Column Adsorption Studies Using Synthetic Hydroxyapatite for Pb(II) Removal from Aqueous Solutions

In the present paper, the adsorptive Pb(II) removal from synthetic aqueous solutions using a 2 cm diameter hydroxyapatite column has been studied through column adsorption experiments by varying column depths (1, 2, 3, 4 cm) and flow rate (10, 15, 22.5 mL/min). Different types of synthetic hydroxiapatites have been involved in experiments. Column design parameters such as critical bed depth and adsorption capacity have been determined from experimental studies. The results revealed the effectiveness of synthetic hydroxyapatite porous beads in Pb(II) removal from aqueous synthetic solutions.

Adsorption of chloro-anilines from solution by modified peanut husk in fixed-bed column

Natural peanut husk (NPH) modified with hexadecyl trimethyl ammonium bromide (CTAB) was used as adsorbent to remove 2,5-dimethoxy-4-chloroaniline (DMCH) from solution in a fixed-bed column. Fourier transform infrared spectroscopy analysis and X-ray fluorescence of NPH and modified peanut husk (MPH) showed that CTAB had been introduced onto the surface of NPH. The effects of flow rate and bed depth on breakthrough curves were studied. The Thomas model and the Yan model were selected to fit the column adsorption data and the results showed that the Yan model was better at predicting the breakthrough curves. The adsorption quantity was up to 6.46 mg/g according to the Yan model. The bed depth service time model was used to calculate the critical bed depth from experimental data and it was directly related to flow rate. As a low-cost adsorbent, MPH is promising for the removal of DMCH from solution.