MODIFICATION OF MOLECULAR SIEVES 13X AND THEIR POSSIBLE USES IN REMOVAL OF PHENOL POLLUTANTS

 The removal of phenol pollutant from water was studied using continuous adsorption process onto MS type 13X. This adsorbent was treated with urea and thiourea to enhance its adsorption ability towards phenol.The preparation step was made by mixing of saturated solution of urea or thiourea, with powder molecular sieve 13X and adding sodium silicat as binder to give homogenous mixture in approximate weight percent, 20 wt% urea or thiourea, 30 wt% binder, 50 wt% MS13X. The molecular sieve samples were dried and shaped in cylindrical particles of about 5 mm diameter and 4-8 mm length. The samples ware characterized by X-ray diffraction pattern, FTIR (Infrared Diffraction) Spectroscopy and surface area measurements. The urea and thiourea treatment, under the experimental conditions employed in the present work, has affected partial their silica and alumina constitution, as shown by their XRD results. Further more, the treatment caused a marked increase in surface area of adsorbents, particularly for urea sample.The FTIR studies show some interesting interactions between the added urea and thiourea with the original substrates, these are mainly hydrogen band type interactions of the urea and thiourea molecules through their –NH  moiety with the –OH group of framework oxygen in the mineral or with the adsorbed water. The urea displayed more significant interaction with molecular sieve 13X than thiourea. Experiments were carried out to investigate the possible use of MS13X and its modified samples for removal of minor amount of phenol from water. Although the investigation was  included investigation the effect of the main operating conditions (high of bed, flow rate, inlet concentration of phenol, and 2Temperatures) on the ability of such adsorbents on the adsorption performance.  Molecular sieve 13X and its dmixtures with urea and thiourea showed good ability to remove phenol from water. The urea modified sample, which has the largest surface area, was the best adsorbent for phenol followed by thiourea treated sample. The results showed also that high percentage removal was achieved by  low phenolic solution flow rate, high bed length and low temperatures, as it's expected for the adsorption processes. The increasing of inlet phenol concentration in water affected largely the driving force and the rate of adsorption, resulted also in higher capacities. While the percentage removal of phenol was decreased by fixed other operating conditions. Excellent degree of phenol removal, greater than 98% was achieved using 0.2 l/h flow rate of 10 ppm phenolic solution and 56 cm bed length at 30ºC, within the present experiments.