Phenol adsorption by modified clay from Northeastern Brazil

Abstract

This research had as objective the use of an adsorbent organoclay to remove the phenol compound, found on a large scale in aqueous effluents of petrochemical industries. The particular clay studied, called 'Chocolate,' originated in the Northeast Region of Brazil, from Campina Grande, Paraíba. Initially the clay sample was treated with sodium carbonate in an aqueous suspension, according to an experimental design (with the variables, sodium concentration, contact time and system temperature). The sodium-containing clay was then treated with a quaternary ammonium salt solution. The adsorption capacity of phenol in this organoclay was estimated using the Langmuir-Freundlich Equation. The adsorptive efficiency, for the best conditions, was approximately 80% of phenol removed from the aqueous phase. The experimental data was fitted to a pseudo-second-order kinetic model. X-ray diffraction results showed that the basal spacing of natural Chocolate clay and organophilic Chocolate clay were 1.549 and 2.092 nm, respectively. The maximum adsorption capacity, with experiments at pH 8.3, at room temperature (27°C), was equal to 12.287 mg g À1.

Adsorption of textile dye and textile effluent using organoclay from Northeast of Brazil

“…purity). The concentrations of HTDMA cations were 1.5 times (organoclay A) and 2.0 times (organoclay B) of the natural clay's cation exchange capacity (CEC) [19]. In this experiment, 10 g of natural clay was dispersed into 500 mL of an HDTMA solution containing 8.16 mmol (organoclay A) and 10.88 mmol (organoclay B) at room temperature (28±1 °C), 6 h contact time, and 210 rpm orbital agitation.…”

“…LI assumes the existence of adsorption sites, all energetically equivalent, where only one molecule is adsorbed per site, without any interaction with molecules adsorbed on the neighboring sites. However, the LFI considers the non-uniformity of the surface adsorption sites [19]. The Langmuir isotherm is shown in Eq.…”

“…1/n (B) Some adsorptive kinetic models have been used in different researches employing the Lagergren models, also called pseudo-first order model and pseudo-second order model, represented by Eqs. C and D [19,20], respectively, where k 1 (min -1 ) and k 2 (g.mg -1 .min -1 ) are the adsorptive kinetic constants: dq t dt = k 1 (q eq -q t ) g q t = q eq (1-e (-k t) ) (C) dq t d q eq k 2 q eq t 1 + t = k 2 (q eq -q t ) 2 g q t = (D)…”