Syntheses and characterization of titanium encapsulated alumino-silicate microspheres (TiAS300/500): Promising materials for the removal of azo dyes from groundwater

Abstract

The present research is concerned with the abatement of dye contamination in groundwater due to certain dye molecules such as Eriochrome black – T (C 20 H 12 N 3 O 7 SNa, EBT), Calcon carboxylic acid (C 21 H 14 N 2 O 7 S, CCD) and Calcon (C 20 H 13 N 2 NaO 5 S, CD) using Titanium encapsulated aluminosilicate microspheres (TiAS300 and TiAS500). Removal efficiency of dye as a function of synthetic dye solutions (EBT, CCD and CD) at various concentrations separately and in the form of 1:1, 2:3 and 3:2 mixtures was investigated at an optimized pH 3 for an equilibrium time of just 20 min. The dye uptake of Ti encapsulated aluminosilicate (AS) microspheres was more efficient than that of virgin AS microspheres by 18 times. The performance of TiAS300 and TiAS500 in the presence of other interfering anions such as nitrate, fluoride and sulfate was quite promising. It was apparent that the use of thermally regenerated adsorbent had to be more in quantity depending upon the cycle number for the complete removal of EBTD as compared with the freshly used TiAS quantities. The characterization studies such as SEM and XRD for the virgin, EBTD loaded and thermally regenerated adsorbents were done. The various stretching frequencies of groups present in the adsorbent materials were confirmed by FTIR. The morphological change from mullite to sillimanite during the loading process and distortion of spherical morphology in Titanium encapsulated ASMS due to hydrothermal process at 300 °C and 500 °C were well ascertained by XRD and SEM studies.