Foam separation for simultaneous removal of rhodamine B (RhB) and cetyl trimethyl ammonium bromide (CTAB)/sodium dodecyl benzene sulfonate (SDBS) from model wastewater was studied. The effect of the surfactant type, aeration rate, temperature, and initial pH on the removal efficiency and enrichment ratio of dye/surfactant were investigated. The results indicated that electrostatic attraction between the dye and surfactant have a great effect on the recovery of the dye and surfactant. The aeration rate has significant influence on the CTAB and RhB removal and enrichment, while the initial pH has a great effect on the RhB removal, but little effect on CTAB removal. Moreover, dissipative particle dynamics (DPD) was employed to simulate the interaction between the surfactant and the dye.

Some inorganic-organic hybrid pigments were fabricated by depositing pigment yellow 12(P.Y.12) on the surface of three inorganic cores with different particle size (white carbon black,microsilica,palygorskite). Effect of inorganic cores on the morphology and structure of the hybrid pigments were systematically investigated by nanoparticle analyzer, Fourier transforms infrared spectroscopy, and X-ray diffraction. Results showed that all three inorganic cores were encapsulated by the organic pigment. The particle size of hybrid pigments was all smaller and had narrower diameter scatter than the original pigment. The water dispersion and flow ability of these fabricated pigments were slightly improved. Thermal and UV-Vis analyses showed that the hybrid pigments had better thermo- and photo-stabilities. Additionally, the properties of the hybrid pigments including color strength, lightness, and yellow hue index were also improved and the modified pigment with white carbon black had the best coloring performance and better heat resistance than original P.Y.12.

The host–guest inclusion complex of calix[6]arene sulfonate (SCA6) with thiazole orange (TO) formed in aqueous solution was studied. Absorption and fluorescence techniques were used for the analysis of this inclusion complex. The addition of calixarene sulfonate leads to a decrease in both absorption and fluorescence intensity of the dye, indicating that the inclusion complex was formed. Simultaneously, the inclusion phenomenon of another cyanine dye, Cy3, with calixarene sulfonate was investigated. The stability constant of the two complexes was determined, and the results were compared. The water solubility of TO dye was increased in the presence of calixarene sulfonate, and further protein labeling experiments suggested that this TO–SCA6 complex can act as a fluorescent probe for labeling of biomolecules.

The modern surfactant industry demands more efficient and environmentally friendly products as environmental regulations become more stringent. Amino acid Gemini surfactants (AAGSs), as the emerging green surfactants of amino acid surfactants, together with the Geminis, which consist of two or more amphiphilic moieties chemically linked by a spacer group, are the most reliable of these efficient green chemicals. With the diversity of structure and topological configuration of the spacer group, AAGSs have stronger aggregation ability and multifarious molecular configuration and aggregation morphology. They are used in various fields such as pharmaceuticals, biomedicine, daily chemicals, oil recovery and environmental treatment. This review contains detailed discussions on the synthesis of AAGSs from natural and non-natural sources using reactions such as Hofmann alkylation and Schotten-Baumann condensation. The physicochemical properties such as low CMC, good emulsification, different micelle forms, high biodegradability, antibacterial ability and biocompatibility are presented. Future research directions of AAGSs are also suggested, including their optimized synthesis, clarification of structure-performance relationships, and exploration of new applications in a wider range of fields.

Modified silica fume powder with oleic acid through coupling agent was prepared based on the in situ utilizing long-chain fatty acids (LCFA) properties of Microthrix parvicella (M. parvicella) in the activated sludge system. The modification was confirmed by XRD and infrared spectrum. The contact angle analysis showed that the modification gave the silica fume powder a hydrophobic surface. The modified silica fume powder had a good combination with M. parvicella from the SEM and Gram staining measurements. The addition of modified silica powder has a certain effect on the settling capacity of sludge, but has little effect on the sludge treatment capacity, while the SVI dropped from 400.1 to 100.0 mL/g. These suggested that the modified silica fume powder could be used as an excellent weight-increasing agent to inhibit sludge bulking. GRAPHICAL ABSTRACT