Performance of organosilane functionalized diatomaceous earth microparticles in removal of mercury from water

Abstract

Natural diatomaceous earth (DE) particles functionalized with 3- mercaptopropyltrimethoxysilane (MPTMS) with specific selectivity for heavy/noble metals have been prepared used as enhanced metal ion adsorbent. Fourier Transform Infrared Spectrometry (FTIR) analysis of the mercapto-DE products revealed that the functional group (-SH) was successfully introduced to the adsorbent surface. Studies involving the removal of Hg(II) ions from aqueous solutions by pristine and MPTMS modified DE products indicated strong initial metal ions concentration and pH dependency. The Hg(II) adsorption kinetics and adsorption isotherms for the MPTMS modified DE particles for Hg(II) observed to follow a pseudo-second-order reaction model and Langmuirian behaviour, respectively. The adsorption reached equilibrium within 60 min with a maximum adsorption capacity of 185 mg·g-1, corresponding to 92 % Hg(II) recovery from 1 mg·dm-3 Hg(II) solution with an adsorbent dosage of 0.25 g (DE)/l. The results show that with further optimisation, a cost effective new and environmentally benign mercapto-DE based adsorbent suitable for removing metals from aqueous solutions can be produced.