Preparation of Graphene Oxide/Attapulgite Composites and Their Demulsification Performance for Oil-in-Water Emulsion

Abstract

In this study, attapulgite (AT) and graphene oxide (GO) nanosheets were grafted together via a silane coupling agent to synthesize attapulgite−graphene oxide (AT−GO) composites and apply them to remove the emulsified oil from the oily wastewater. The structure and morphology of the AT−GO composites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, zeta potential measurements, and transmission electron microscopy. The amphiphilicity of the AT−GO composites was evaluated by visual observation of their distribution in the oil−water mixture. The results showed that the AT−GO composites have been successively prepared and have good amphiphilic and interfacial activity. The effects of the pH, demulsifier dosage, temperature, and the mass ratio of AT and GO (R A/G ) in the composites on the demulsification performance of AT−GO were studied. It was found that the demulsification process could be completed efficiently and quickly at room temperature. Under optimal demulsification conditions, the demulsification efficiency is above 95%. The demulsification mechanism was studied and discussed. It is believed that the interaction behavior between the AT−GO material and the emulsified molecules of asphaltenes is a key for the demulsification. Once the nanoparticles are combined with the emulsified molecules, the external stirring, vibration, and other mechanical actions provide them enough kinetic energy to destroy the protective film at the oil/water interface and then promote the merging of dispersed oil droplets to realize the oil−water separation.

A facile approach to synthesize CdS–attapulgite as a photocatalyst for reduction reactions in water

“… 51 In the spectrum of ATP, on characteristic peaks at 800 and 1032 cm −1 can ascribed to the symmetric stretching vibration of Si–O and unsymmetric stretching vibration of Si–O–Si respectively. 43 And the broad-band between 3300 and 3500 cm −1 is due to the skeletal vibrations of O–H. 43 The major characteristic vibration peaks related to CdS and ATP can be clearly found in the composites, which implying that the structure of CdS remains intact after composited with ATP.…”

“… 43 And the broad-band between 3300 and 3500 cm −1 is due to the skeletal vibrations of O–H. 43 The major characteristic vibration peaks related to CdS and ATP can be clearly found in the composites, which implying that the structure of CdS remains intact after composited with ATP.…”

“…The adsorption, carrier and catalytic properties of ATP make it a promising catalyst in sewage disposal. [42][43][44] In the CdS-ATP composites, ATP may not only play a role in xing and avoiding agglomeration, but also can reduce light corrosion and improve light tolerance. In addition, as an ideal photocatalytic carrier material, ATP can also provide many microreaction sites for photocatalytic reaction.…”

3D-printing of attapulgite monoliths with superior low-temperature selective catalytic reduction activity: the influence of thermal treatment

“…As a low-cost and widely sourced clay, attapulgite (ATP) possesses a unique layer chain structure, high specific surface area and cation exchange capacity. 1,2 Accordingly, attapulgite has been widely utilized as an important basic material in the aspect of environmental protection, 3,4 adsorption separation 5,6 and composite materials. 7,8 Nevertheless, powdery attapulgite is restricted to a certain extent due to the size and structure requirements in practical applications.…”

Adsorption Properties and Mechanism of Attapulgite to Graphene Oxide in Aqueous Solution

“…Its main chemical composition is SiO 2 [ 21 ]. Attapulgite not only has good surface area and high surface activity, but studies have shown that GO and attapulgite can be modified and reconstituted by ultrasonic and magnetic stirring methods, and have good adsorption effects on aniline, emulsified oil, propranolol, and Pb(II), U(VI), and plasma [ 22 , 23 , 24 , 25 , 26 ]. However, there are few studies on attapulgite as an adsorbent for the removal of GO in aqueous environments.…”