Evaluation of Dye Adsorption Onto SBA‐15 Using Image Analysis

Abstract

In this work, the reliability of image analysis for the numerical evaluation of Basic Red 46 (BR 46) dye adsorption process was studied. The image analysis was carried out on dye adsorbed onto SBA‐15 mesoporous silica, by use of Image‐Pro Plus software. Pixel‐specific calibration curves were derived and used to obtain dye concentration from the three different primary color channels (red, green, and blue) recorded at each pixel. In order to establish credibility of this method for quantification of adsorption processes, these data were compared with dye adsorption parameters obtained by UV‐vis analysis. Among the three different primary color channels, the best results were obtained when the blue color channel was applied. In this case, the average relative error was 0.86%. The obtained results showed that a dye adsorbed on SBA‐15 can be determined with the use of Image‐Pro Plus with the same sensitivity as with the use of spectrophotometric analysis for the determination of changes in dye concentration during the adsorption process.

Mesoporous silica-based sensor for colorimetric determination of Basic Yellow 28 dye in aqueous solutions

“…The maximum achieved sorption capacity is 80 mg/g. The fast sorption time of other cationic dyes onto SBA-15 was reported previously, namely for the Basic Red 46 [26] (5 min), Basic Violet [27] (5 min) and Methylene Blue (10 min), whereas equilibrium time for sorption of anionic dyes was longer than in this study, for example for Reactive Red 2 and Safranin O was 30 min, and for Congo and Neutral Red 80 min [28]. The influence of the mass of sorbent was tested at initial concentration of the dye solution 20 mg/dm 3 and pH 8 in a period of 5 minutes, varying the sorbent mass in the range of 0.01 g to 0.2 g. Figure 2 displays the effect of the sorbent mass on the sorption capacity of BY28 dye onto SBA-15 mesoporous silicates.…”

“…Namely, sorption capacity varies from 67 (at pH 2) to 77 mg/g (at pH 8). It was reported in literature that sorption of cationic dyes onto SBA-15 rose with an increase of pH from 2 to 8 [26,29], while for the anionic dyes the opposite trend was detected [28]. The high sorption capacity of cationic dyes in alkaline environment was described by electrostatic and hydrogen bond interactions since SBA-15 is charged negative at high pH.…”