Natural Palygorskite as an Industrial Dye Remover in Single and Binary Systems

Abstract

Layered or fibrous clay minerals are used as adsorbents because they have good performance to remove inorganic and organic species. In this work, a Brazilian fibrous clay mineral was applied to remove Remazol Yellow GR industrial dye from simple and binary systems; this was performed in the presence of lead in the latter case. The adsorption efficiency was investigated under various conditions of pH, time, temperature and dye concentration. The experimental data were fitted to the kinetic pseudo-first-and pseudo-second-order models, and the isotherms were fitted to the Langmuir and Freundlich models. The maximum adsorption capacity was 20.08 mg g -1 at pH 2, 240 minutes and 298 K, and these data were better fit by the kinetic pseudo-second-order model. The equilibrium study was fitted to the Langmuir model at 298 K and Freundlich for other temperatures and binary systems. The dye sorption in the presence of lead was decreased to 15 mg g -1 . Therefore, palygorskite behaved as a promising solid for treating effluents.

A multi-site mechanism model for studying Pb and Cu retention from aqueous solutions by Fe-Mg-rich clays

“…The typical plateau in the graph of pH f vs. pH i , which corresponds to the equilibrium between the protons and the clay surface and defines pH PZC , was observed at pH ∼8.5 for PCM, and ∼9 for SCM and MCM, respectively (Figure 1). The results are in general agreement with literature data for palygorskite (PZC = 7-11) (Pereira et al, 2016;Rusmin et al, 2016;Acebal & Vico, 2017). The SCM and MCM samples studied show greater PZC values than those reported for the Brazilian nontronite (PZC ≈ 4) (Guerra et al, 2016) and NAu-2 from the Source Clays Repository (PZC = 7.2) (Jaisi et al, 2008), however.…”

Preparation, Characterization of Polyvinyl Alcohol/Activated Carbon (PVA/AC) Composite and the Removal of 4-Nitrophenol (4-NP)

“…The point of zero charge was determined by a reported procedure [8,9]. The procedure can be described as follows: to a series of 50 mL conical flasks, 30 mL of 0.1M NaCl solution was added.…”

“…4 shows that the pHpzc of the PVA/AC was approximately 3. In other words, at this pH, the PVA/AC surface has zero charge [9]. Therefore, when solution pH increases above pHpzc, the surface of PVA/AC is negatively charged, when it decreases below the pHpzc value the surface of PVA/AC is positively charged because of protonation [11,12].…”

“…log qe = log k + (1/n) log Ce (9) k(mg/g) and n are the adsorbent capacity, the heterogeneous factor respectively and connected to intensity of Freundlich isotherm. According to Freundlich isotherm, adsorbent surface is heterogenous [29] and adsorption capacity is relative to the concentration of adsorbed phenol at equilibrium.…”

Al (III) removal from wastewaters by natural clay and coconut shell

“…There are various forms of clay in the nature, such as kaolinite, smectite, illite, chlorite, and talc. Given clay's abundance in nature, as well as its affordability and ease of supply, coupled with its high level of specific surface area and replacement capabilities, it is only natural to see many studies in the literature, discussing the use of clay minerals as adsorbents (Silva et al, 2016;Araujo et al, 2013). In order to ascertain the surface characteristics of clay and coconut shell adsorbents, SEM images were taken following activation using H2SO4 and adsorption process (See Figure 2a-d).…”