Preparation of organically functionalized silica gel as adsorbent for copper ion adsorption

Abstract

A novel adsorbent (AMPS-silica) was synthesized by bounding AMPS (2-acrylamido-2-methylpropanesulfonic acid) onto silica surface, which functioned with γ-methacryloxypropyltrimethoxysilane reagent. The adsorbent was characterized by nitrogen adsorption/desorption measurement, thermogravimetric analysis (TGA) and potentiometric titration analysis. The TGA result indicated that the surface modification reactions introduced some organic functional groups onto the surface of silica. The surface area of AMPSsilica was 389.7 m 2 /g. The adsorbent was examined for copper ion removal in series of batch adsorption experiments. Results showed that the adsorption of Cu 2+ onto AMPS-silica was pH dependent, and the adsorption capacity increased with increasing pH from 2 to 6. The adsorption kinetics showed that Cu 2+ adsorption was fast and the data fitted well with a pseudo second-order kinetic model. The adsorption of Cu 2+ onto AMPS-silica obeyed both Freundlich and Langmuir isotherms, with r 2 = 0.993 and r 2 = 0.984, respectively. The maximum Cu 2+ adsorption capacity was 19.9 mg/g. The involved mechanism might be the adsorption through metal binding with organic functional groups such as carboxyl, amino and sulfonic groups. Cu 2+ loaded on AMPS-silica could be desorbed in HNO 3 solution, and the adsorption properties remain stable after three adsorption-desorption cycles.

Phosphonate Modified Silica for Adsorption of Co(II), Ni(II), Cu(II), and Zn(II)

“…Therefore Cu(II) which has the smallest ionic radii has the biggest potential ionic. The above fact related to the effect of atomic radii on adsorption was also supported by several earlier workers [41,[43][44] …”

“…The kinetics parameter of metal ions adsorption calculated using models of 1 [42][43][44] are shown in Table 4. According to the value of the correlation coefficient (R 2 ), the kinetics of Cu(II) adsorption on PMS order indicating that the adsorbent does not contain a large excess amount available for those ions so that concentration of active sites on the adsorbent declines linearly to that of the adsorbate during adsorption.…”

SINTESIS DAN UJI ADSORPSI SILIKA TERMODIFIKASI 3-Aminopropiltrietoksisilan (APTS) PADA LOGAM Cu (II) DALAM LARUTAN

“…Unsur tembaga yang melewati ambang batas maksimum pada media tertentu juga dapat mencemari lingkungan air. Limbah yang mengandung Cu 2+ dapat berasal dari buangan bahan seperti dari industri galangan kapal yang menggunakan cat anti pencemaran (anti fouling paints) [1], industri pengolahan kayu, PCB (Printed Circuit Board), limbah domestik, dll.…”

“…Modifikasi ini mendapatkan perhatian besar karena kapasitas adsorpsi yang tinggi, dan selektivitas yang tinggi [1], [3]. Selain itu gugus organik sebagai atom pendonor elektron memiliki muatan negatif yang dapat menetralkan muatan ion logam, sehingga gugus organik dapat berikatan dengan ion logam melalui ikatan kovalen koordinasi membentuk senyawa kompleks [4].…”

“…Kapasitas adsorpsi terlihat konstan saat uji adsorpsi pada pH 5 sampai pH 6. Dengan demikian kereaktifan gugus fungsional mempengaruhi interaksi dengan ion logam pada permukaan adsorben silika termodifikasi APTS [1]. Mulai dari pH rendah sampai pada pH optimum memberikan peningkatan adsorpsi bagi ion Cu 2+ , selanjutnya setelah mencapai kondisi optimum maka adsorpsi cenderung stabil.…”