The increase of surface area of a Brazilian palygorskite clay activated with sulfuric acid solutions using a factorial design

Abstract

Palygorskite is fibrous clay in which the structural tetrahedral and octahedral layers are organized in a way that structural channels are formed, leading to high surface area. However, impurities inside the channels and aggregated ones considerably reduce the available area. In order to increase the surface area, an activation treatment can be considered useful. The goal of this work is the activation of palygorskite from Guadalupe, Piauí, via sulfuric acid treatment using a two-level factorial design. The influence of three parameters (solution molarity, temperature and time) on BET surface area was determined. Moreover, samples were characterized via X-ray diffraction (XRD) and fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The largest surface area (282 m 2 /g) without considerable changes in clay structure and morphology was found in a sample treated with 5M H 2 SO 4 at 70°C for 1h. The main parameters that favored the improvement of the surface area were the solution's molarity, temperature and their interaction.

Purification of raw palygorskite: a comparative study involving different processes and dispersing agents

“…Methodology: the methodology was based on references [19,21]. Raw Brazilian Pal was first sieved through a 325 mesh sieve to remove part of the impurities, such as quartz.…”

“…From this, through physical separation methods, the non-Pal particles can be removed [8,19]. To remove remaining organic matter and carbonates, acid activation can be done by using oxidizing reagents, such as hydrogen peroxide (H 2 O 2 ) and strong acids, as hydrochloric acid (HCl) and sulfuric acid (H 2 SO 4 ) [20,21]. The acid activation allows the improvement of the physicochemical properties of the clay, such as adsorption, specific surface area, cation exchange capacity, among others [22,23].…”

Synthesis of acidified palygorskite/BiOI with exceptional performances of adsorption and visible-light photoactivity for efficient treatment of aniline wastewater

“…The bands between 512 cm − 1 and 1383 cm −1 belong to the stretching vibrations of the tetragonal crystal links of BiOI (Yu et al, 2012). For AP-1.0, the bands at 800 cm −1 and 1104 cm −1 are assigned to the vibration of Si-O-Si in the acidified Pal structure (Boudriche et al, 2011;Oliveira et al, 2013). The band at 1620 cm −1 is attributed to the bending mode of water molecule (Mendelov, 1973).…”

Estudo Da Corrosão De Aço Carbono Em Diferentes Meios E O Tratamento Por Eletrólise

“…soluções simples e de baixo custo como na área estética e cosmetologia, assim como na área de saúde. (OLIVEIRA et al, 2013) [12] The effect of natural and organophilic palygorskite on skin wound healing in rat Organofilização (LUCIANO et al, 2014) [9] Facile fabrication of carbon/atapulgite composite for bleaching of palm oil Carbono ativado associado à atapulgita (TIAN et al, 2015) [14] hidrofóbicas e a pilarização, onde o ajuste da distância internuclear é feito pela intercalação de cátions inorgânicos de diferentes tamanhos [15]. A ativação ácida também melhora o desempenho ao utilizar ácidos fortes para limpeza de canais e expandir área de superfície e poros destes filossilicatos.…”