Amphoteric modified vermiculites as adsorbents for enhancing removal of organic pollutants: Bisphenol A and Tetrabromobisphenol A. (September 2017)

• Record Type: Journal Article
• Authors: Liu, Shuai; Wu, Pingxiao; Chen, Meiqing; Yu, Langfeng; Kang, Chunxi; Zhu, Nengwu; Dang, Zhi
• Is Part Of: Environmental pollution. Volume 228(2017)
• Page Start: 277
• Page End: 286
• Publication Date: 2017-09
• Subjects: Vermiculite -- Amphoteric surfactant -- Adsorption -- BPA -- TBBPA; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2017.03.082
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Three novel organic vermiculites (VER) modified by amphoteric surfactants (BS, SB and PBS) with different negatively charged groups (carboxylate, sulfonate and phosphate) were demonstrated and used for removal of bisphenol A (BPA) and tetrabromobisphenol A (TBBPA). The difference in the structure and surface properties of modified vermiculites were investigated using a series of characterization methods. BS and SB surfactant mainly adsorbed on the surface and hard to intercalate into the interlayer of VER, while both adsorption and intercalation occurred in PBS modification. This difference resulted in different packing density of surfactant and hydrophobicity according to the results of contact angle, and affect the adsorption capacities ultimately. The adsorption of two pollutants onto these modified vermiculites were very fast and well fitted with pseudo-second-order kinetic model and Langmuir isotherm. PBS-VER exhibited the highest adsorption capacity (92.67 and 88.87 mg g −1 for BPA and TBBPA, respectively) than other two modified vermiculites in this order PBS-VER > BS-VER > SB-VER. The ionic strength (Na +, Ca 2+ ) and coexisting compounds (Pb 2+, humic acid) have different effects on the adsorption. PBS-VER had a good reusability and could remove ionic (methylene blue and orange G) and molecular (BPA) pollutants simultaneously and effectively due to the function of amphoteric hydrophilic groups and alkyl chains. The results might provide novel information for developing low-cost and effective adsorbents for removal of neutral and charged organic pollutants. Graphical abstract: Highlights: Different structures of organic vermiculites were prepared from different types of amphoteric surfactant. The removal of bisphenol A (BPA) and tetrabromobisphenol A (TBBPA) were very fast and ascribed to hydrophobic interactions. The maximum adsorption capacity was 92.67 mg g −1 for BPA and 88.87 mg g −1 for TBBPA and adsorbents were easy to regeneration. The amphoteric modification endows the potential for vermiculite to remove ionic and hydrophobic pollutants simultaneously.