Chemisorption of hydrogen sulfide on halloysite‐based porous clay heterostructures modified with potassium permanganate

Abstract

Hydrogen sulfide gas is harmful to human health and causes corrosion of electronic devices, when it is present in indoor air. Porous clay heterostructures (PCHs) provide a new type of material for catalysis, adsorptive separations and as H 2 S sensors because their large pores allow access to their active interiors. PCHs posses a large adsorptive surface area (400-900 m 2 g −1 ) and a unique combination of micro-and mesoporosity. In this work, PCHs were synthesized by the polymerization of tetraethoxysilane (TEOS) in the micelles, which were assembled by mixing tubular halloysite powders and cetyltrimethylammonium bromide (CTMAB). Both as-synthesized PCHs and pristine halloysite were impregnated with KMnO 4 by equal-volume mixing to obtain chemosorbents. The mass percentages of KMnO 4 ranged from 5 to 30 wt%. The samples were characterized by using N 2 adsorption, X-ray diffraction (XRD), diffuse reflectance ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscope (TEM) and infrared spectroscopy. The dynamic adsorption of the chemosorbents for hydrogen sulfide was evaluated with a fixed bed. The results show that the PCH-based chemosorbents exhibit better H 2 S breakthrough performance due to their rich porous structure, the samples with 15-20 wt% KMnO 4 possessing the highest activity. This study shows that the KMnO 4 /PCH chemosorbents can effectively remove H 2 S from indoor air at room temperature. 

Synthesis of new porous clay heterostructures: The influence of co-surfactant type

“…PCH are characterized by attractive properties like high specific surface area (200e1000 m 2 /g), high thermal stability, design capacity of pores with controllable sizes and distributions, high adsorption capacity of volatile organic compounds (400e900 m 2 /g) and alkaline metals from aqueous solutions [12,13]. The properties (textural properties, acidity and thermostability) of PCH can be adjusted by using different raw materials and various conditions of synthesis.…”

Kinetic studies on adsorption behavior of methyl orange using modified halloysite, as an eco-friendly adsorbent

“…Within the literature, similar halloysite/ CTAB ratios were used in the modification process. In a study conducted by Lu et al, 0.5; 1.0; 1.2 g CTAB were used with 10 g halloysite [34]. Cavallaro and coworkers 2 g of alkyltrimethylammonium bromide was used for the modification of 4 g halloysite [31].…”