Optimization of Cd(II) adsorption condition by glycine-modified silica-based adsorbent using central composite design

Abstract

Silica gel (SG) is one of common adsorbent on solid phase extraction for preconcentration. Due to the low selectivity and effectiveness of adsorption to metal ions, SG should be modified. The SG was modified with d-glycine (Si-Gly) using 3-aminopropyltrimethoxysilane and glutaraldehyde as a crosslinker. Capability of Si-Gly as adsorbent for cadmium ions (Cd) was investigated using batch adsorption. The result was proved by infrared spectra. The optimum condition of Cd adsorption by the Si-Gly was obtained at pH 5, with 0.3 g of adsorbent and 11 minutes of contact time. The percentage of Cd adsorption at the optimum condition by the Si-Gly (99.34%) which is greater than the SG (89.03%). The maximum adsorption capacity of the Si-Gly is 9.77 mg/g, obtained at 400 mg/L. The Cd(II) adsorption on the SG and the Si-Gly follow the Langmuir isotherm equation.

Optimization of Cr(VI) Adsorption on Eugenol-Silica Gel Composites Using Behnken Box Design

“…Then the estimation of the regression coefficient based on the analysis using the response surface model can be concluded that follows the equation: The equation above shows that: if the other variables are constant then the Y value will change automatically by the constant value, that is -12.41; if other variables are constant, the Y value will change by 0.924 for every one X1 unit; if other variables are constant, the Y value will change by 3,276 for every X2 unit; if the other variables are constant then the Y value will change by 76.4 every one unit of X3. The quadratic variables (X1 2 , X2 2 and X3 2 ) have a minus sign indicating the meaning that the quadratic variable has an antagonistic effect on the response, while the linear and interaction variables (X 1 X 2 , X 1 X 3 , X2X3) show a synergistic effect on the response as seen from the positive sign on the coefficient number [6].…”

“…At that time the adsorption reaction equilibrium has occurred because the adsorbate molecules have entered the pores of the adsorbent. Increasing the contact time can indeed increase the adsorption rate, but at the contact time that exceeds the equilibrium limit it can cause a decrease in the active adsorption center which causes fewer metal ions to be adsorbed and results in a decreased response or no desorption has occurred [6].…”

Fotodegradasi Metilen Biru oleh Metal Organic Framework (MOF) Fe-PTC dengan Penambahan H2O2 dan Dioptimasi Menggunakan Desain Box Behnken

“…Tabel 3 menunjukkan analisis varians (ANOVA) yang digunakan untuk menguji kelayakan model yang digunakan. Jika nilai P hitung kurang dari 0,05 maka hal itu menunjukkan bahwa data signifikan secara statistika [30]. Pada penelitian ini nilai P-hitung untuk variabel independen konsentrasi H 2 O 2 (X 2 ) dan waktu kontak (X3) secara berturut-turut adalah 0,035 dan 0,009.…”

Optimization of Cadmium Removal Using Tetraethylene Glycol-Modified Silica-Based Adsorbent via Response Surface Methodology

“…Modifications need to be performed to increase silica adsorption capability. Several previous studies have reported the modification of silica-based solid-phase materials for the adsorption of Cd(II) ions, including the amino acid ᴅ-glycine [5]; Pyridine 2,6-diylbis (2,2 '(azamethane-1-ylidene) 4-bromophenol) (L); and silica-polyethylene glycol (PEG) [6]. Another adsorbent modification on silica could be used TEG (tetraethylene glycol).…”