Silica Gels from Coal Fly Ash as Methylene Blue Adsorbent: Isotherm and Kinetic Studies

Abstract

A lot of dye pollutants were released in the aquatic environment as waste from industrial coloring process. This research aimed to study silica gels (SG) as a potential adsorbent to remove the dyes. The SG can be synthesized from coal fly ash (FA), which is industrial solid waste rarely utilized, using the sol-gel method. Its properties were then characterized by FTIR, XRD, SEM, and isothermal ads-des N2.As a result, FTIR spectra and XRD diffractogram exhibited the successfully SG synthesized from FA with the amorphous structure. The image analysis using SEM demonstrated that SG particles are spherical. The isotherm type, based on isotherm ads-des N2, is type II without hysteresis loop which represents the nonporous material SG with the surface area and pore diameter of 25.977 m 2 /g and 1.52 nm, respectively. The adsorption capacity performance of SG to remove methylene blue (MB) as a basic dye is 62.70 % which is higher than FA, following Langmuir isotherm adsorption model. The kinetics of adsorption rate of SG are based on the pseudo second order models accelerated by 3.37 times faster than FA.

Kinetics of Adsorption Competition of Pb-Cu and Pb-Methylene Blue in Aqueous Solution using Silica Gels from Coal Fly Ash

“…Other than that, conversion of fly ash to SG was one of the strategies to increase the adsorption capacity. In the previous studies, the adsorption capacity of methylene blue using silica gel increased by 27.64% compared to fly ash (Sulistiyo et al, 2017).…”

An Alternative and Simple Method for the Preparation of Bare Silica Nanoparticles Using Sugarcane Waste Ash, an Abundant and Despised Residue in the Brazilian Industry

“…This is an expected result since these nanoparticles are bare and the only possible interaction is the electrostatic interaction between the negative charges on the surface of the silica nanoparticles and the positive charge of MB. 40,[42][43][44][45][46][47] This way this type of interaction can only generate a single layer of molecules on the surface of the nanoparticles, and after the neutralization of the surface, there is a saturation of the surface.…”

Sintesis Silika Gel Berbasis Fly Ash Batu Bara PLTU Paiton Sebagai Adsorben Zat Warna Rhodamin B

“…Mengacu pada kandungan SiO2 pada abu sekam padi dan baggas tebu yang dapat dimurnikan menjadi material silika gel dengan kemurnian 98-99% [8] dan [9], maka abu terbang juga dapat diubah menjadi silika gel. Pada penelitian sebelumnya [10], silika gel berhasil disintesis dari abu terbang yang memiliki kapasitas adsorpsi terhadap zat warna metilen biru meningkat 62,70% dibanding abu terbang. Kemampuan adsorpsi silika gel dipengaruhi oleh gugus silanol (Si-OH) dan gugus siloksan (Si-O-Si) pada permukaannya yang reaktif.…”