Adsorption of the herbicide S-Metolachlor on periodic mesoporous organosilicas

Periodic Mesoporous Organosilicas as adsorbents for the organic pollutants removal in aqueous phase

“…The stability of Si-C bond during the synthesis and after oxidation of acid-functionalized PMOs was confirmed by the absence of characteristic siloxane Q n (Si(OSi) n (OH) 4Àn ) signals which usually appear between 100 and 112 ppm [25]. The 13 C spectrum of SBA-15-SO 3 H displays three well resolved signals at 11, 18 and 54 ppm (Fig. 4b) assigned to carbon Si-CH 2 , -CH 2 -CH 2 -CH 2 -and HO 3 S-CH 2 -, respectively [19].…”

“…The remarkable catalytic activity of these materials was also observed in the literature on many reactions [9][10][11]. Only a few references were found in the literature concerning the use of adsorptive properties of PMOs for the removal of organic pollutants in aqueous phase [12][13][14]. In addition, the molecules studied in these papers are molecules with a relatively small size that easily adsorb on zeolites or activated carbons which are efficient adsorbents and less expensive than the PMOs.…”

“…29 Si cross-polarization magic-angle spinning (CP MAS) NMR spectra were collected using 4 ls 1 H p/2 pulse; 8 ms contact time 5 kHz spinning rate and 5 s recycle delays. 13 C CP MAS NMR spectra were collected with a 4 ls 1 H p/2 pulse, 1 ms contact time, 6 kHz spinning rate and 4 s recycle delay. Thermal gravimetric-differential thermal analysis (TGA-DTA) was performed in platinum crucibles using a SDT Q600 microbalance (TA Instruments) from 30 up to 900°C under nitrogen atmosphere (50 mL min À1 ) at a heating rate of 2°C min À1 .…”

Evaluation of phenylene-bridged periodic mesoporous organosilica as a stationary phase for solid phase extraction

“…Also, hydrophobic and aromatic -interactions between aromatic rings in the pore walls of the Ph-PMO sorbent and the pesticides should be considered. At its isoelectric point (pH around 4 [15]), the surface of this material is essentially neutral, so hydrophobic and aromatic interactions prevail over electrostatic forces. The surface of Ph-PMO is positively charged below pH 4 and negatively charged above pH 4.…”

“…for organic molecules. Recently, the adsorption of toxic organic pollutants such as benzene and 4-nitrophenol [14], and the herbicide S-metolachor [15], in ethylene-and phenylene-bridged PMOs (Ph-PMO) was examined and Ph-PMOs were found to clearly surpass ethylene-bridged PMOs and related all-silica materials in this respect.…”