Paraquat adsorption on porous materials synthesized from rice husk silica

Abstract

The goal of this work was to utilize rice husk silica (RHS) and porous materials synthesized with RHS, including mesoporous material (MCM-41) and microporous materials (zeolite NaY and NaBEA), for adsorption of herbicide paraquat. The adsorption occurred although cation exchange and the capacity decreased in the following order: NaY > NaBEA > MCM-41 > RHS, consistent with the amount of Al. The adsorption on all adsorbents fitted well with the Langmuir model and the maximum adsorption capacity of 185.2 mg/g-adsorbent was obtained on NaY. In addition, blue dye in commercial grade paraquat did not interfere with paraquat adsorption. Although MCM-41 was the most efficient adsorbent for the blue dye, RHS was favorable in terms of production cost. A mixture of NaY and RHS is recommended for simultaneous adsorption of paraquat and blue dye.

Dynamic Self‐Assembly Adhesion of a Paraquat Droplet on a Pillar[5]arene Surface

“…Paraquat is aw idely used herbicide. [11][12][13][14] To address the challenging problem, we introduce host-guest chemistry onto surfaces to control the dynamic self-assembly binding of the paraquat droplet to the surface.T he pillar[n]arenes, [15][16][17][18][19] composed of hydroquinone unit linked by methylene bridges at para positions,are rigid as well as easily functionalized with various substituents. [20,21] Theunique cavity structure and easy modification of pillar[n]arenes endow them with an outstanding ability to selectively bind different kinds of guests, [22][23][24] which provides au seful platform for the construction of the functional surface.…”

Comprehension of paraquat adsorption on faujasite zeolite X and Y in sodium form

“…Each supercage has a diameter of 1.3 nm and four open windows with a diameter of 0.74 nm (Guisnet and Gilson, 2002). The Si/Al ratios of NaX and NaY from our works are 1.2 and 2.2, respectively (Rongchapo et al, 2013(Rongchapo et al, , 2015. The presence of an Al atom in the zeolite framework generates a negative charge which requires a charge balancing cation.…”

“…From our previous work (Rongchapo et al, 2013) zeolite NaY had the maximum paraquat adsorption capacity of 185 mg/g-adsorbent, higher than rice husk silica, zeolite NaBEA, NaZSM-5, and mesoporous MCM-41. The adsorption was proposed to occur via ion exchange and increased with Al content in the adsorbents.…”

“…With a high solubility, paraquat can easily contaminate and accumulate in surface water (Pateiro-Moure et al, 2010). There are several reports on paraquat removal from aqueous solutions by adsorption on various porous materials including silica (SiO 2 ), zeolite NaBEA, NaY, NaX, mesoporous materials MCM41 and Al-MCM-41 (Brigante and Schulz, 2011;Ibrahim and Jbara, 2009;Nur et al, 2005;Rongchapo et al, 2013Rongchapo et al, , 2015.…”

Removal of Paraquat from Aqueous Solutions onto Zeolite LTL

“…From a review of the literature it was found that siliceous compound [3], clay [4][5], bentonite [6], diatomaceous earth [7] and zeolite Y (NaY) [8] were reported as adsorbents for paraquat removal. Rongchapo et al [9] reported that the exchange capacity of paraquat depends on the Si/Al ratio. They found that NaY (Si/Al ratio of 2.2) has a higher exchange capacity than NaBEA (Si/Al ratio of 14.2).…”