Removal of Rhodamine B from aqueous solution using silica extracted from rice husk

Abstract

Global annual production of rice husk is approximately 120 million tons. It doesn't easily biodegrade, resulting in disposal problems. This paper therefore, investigated the use of silica obtained from the burning of the raw rice husk in open air (RHSA) and in a Muffle Furnace at 540 °C (RHSO). The efficiency of the two silica samples in removing Rhodamine B (RB) from aqueous solution was tested using different process parameters. 89% silica was obtained from either method. The removal of RB was more possible on RHSA than on RHSO. This was revealed by calculated Langmuir R L values of 0.152 for RHSA and 0.558 for RHSO. This was also supported by the obtained Temkin isotherm equilibrium constants values of 3.379 and 0.677 L/mg for RHSA and RHSO respectively. Langmuir monolayer capacities of 6.0 and 6.87 mg/g were obtained for RHSA and RHSO respectively. Increased in mass of RHSA or RHSO greatly enhanced RB removal (65% with 0.05 g to 98% with 0.5 g for RHSA). Optimal removal conditions on each sample were; temperature 27 °C, mass adsorbent 0.5 g, pH 7.05, contact time 24 h and 10 mg/L of RB initial concentration. The RB removal was negatively affected by ionic strength, decreasing from 84 to 46% for RHSA and 60-41% for RHSO with increase in ionic strength from 0.00 to 2 M. The two adsorbents are efficient in RB removal and easily regenerated as it is purely a physical process.

Determination of Sudan I and II in Food by High-Performance Liquid Chromatography after Simultaneous Adsorption on Nanosilica

“…The initial concentrations of Sudan I and II were 30–5000 µ g·L −1 , the adsorption equilibrium time was 120 min, the pH was 3, and [KCl] = 1 mM. The coefficient of determination ( R 2 ) for the linear fit of the data was greater than 0.99, indicating that the dyes are adsorbed by monolayer physical adsorption, and the adsorption centers on the surface are homogeneous [ 25 ]. The maximum adsorption capacity ( q m ) and adsorption constant ( K L ) for Sudan I were 0.619 mg g −1 and 2.132, respectively, whereas those for Sudan II were 0.699 mg g −1 and 1.573, respectively.…”

“…Further, nanosilica can be easily fabricated from rice husk and is a low-cost, ecofriendly, and abundant adsorbent [ 19 – 22 ]. Concerning its use as a sorbent, nanosilica has been mainly used to adsorb hydrophilic substances such as methylene blue [ 23 , 24 ] and Rhodamine B [ 25 ], whereas the adsorption of other organic dyes by other adsorbents has been studied intensely [ 26 – 31 ]. However, to date, the adsorption of hydrophobic organic dyes onto nanosilica has not been reported.…”

Batch mode treatment of wastewater from the Maroua artisanal tannery using silica extracted from rice husks and silica/sand mixture

“…The silica used in this work was synthesized by [13]. The rice husk collected from the rice processing unit of SEMRY (Cameroon) was used as a raw material for the preparation of the silica.…”

“…The valorization of solid agricultural wastes as precursors for adsorbents synthesis is of high interest because it's low cost and in the same time represents a good way to solve the problem of their disposal in the environment. It has been reported in the literature that silica prepared from rice husk ash exhibit good efficiency for dye removal [12,13]. Therefore, its combination with sand may be an interesting option to improve the adsorption process performance.…”

Influência da catálise ácida e básica na síntese de xerogéis de sílica para a adsorção de azul de metileno em meio aquoso

“…Aliado a isso, a sílica tem uma série de propriedades que lhe confere promissoras aplicações como adsorvente, como altas estabilidades química e térmica, elevada área superficial específica e diâmetro de poros que varia de microporos a mesoporos (Price et al, 2008), o que explica a vasta gama de materiais à base de sílica desenvolvidos para adsorção de corantes reportada na literatura (Bongur et al, 2016;de Farias et al, 2018;Han et al, 2016;Huang et al, 2011;Li et al, 2020;J. Liu et al, 2013;Roghanizad et al, 2020;Sun et al, 2015;Tsamo et al, 2020).…”