Inorganic/organic hybridization is often employed to synthesize unctional materials but seldom considered in industrial wastewater treatment. Dye conjugate hybridization was proposed by immobilizing the anionic (e.g. congo red)-cationic (e.g. methylene blue) dye complex with growing calcium carbonate. The 3D-morphology and structure of the conjugate hybrid were characterized and the mechanism of formation elucidated. The shell-core structural hybrid was formed and then stacked into cubes. Applied to treatment of concentrated organic wastewaters, the simple single-step hybridization performed adsorption, flocculation and ionic complexation and exhibited a high level of removal of organic substances. This work provides a convenient, cost-effective and environmentfriendly wastewater treatment by "using waste to treat waste".

Background: Health risk from exposure of perfluorochemicals (PFCs) to wildlife and human has been a subject of great interest for understanding their molecular mechanism of toxicity. Although much work has been done, the toxigenicity of PFCs remains largely unknown. In this work, the noncovalent interactions between perfluorooctane sulfonate (PFOS) and serum albumin (SA) and DNA were investigated under normal physiological conditions, aiming to elucidate the toxigenicity of PFCs. Results: In equilibrium dialysis assay, the bindings of PFOS to SA correspond to the Langmuir isothermal model with two-step sequence model. The saturation binding number of PFOS was 45 per molecule of SA and 1 per three base-pairs of DNA, respectively. ITC results showed that all the interactions were spontaneous driven by entropy change. Static quenching of the fluorescence of SA was observed when interacting with PFOS, indicating PFOS bound Trp residue of SA. CD spectra of SA and DNA changed obviously in the presence of PFOS. At normal physiological conditions, 1.2 mmol/l PFOS reduces the binding ratio of Vitamin B2 to SA by more than 30%. Conclusion: The ion bond, van der Waals force and hydrophobic interaction contributed to PFOS binding to peptide chain of SA and to the groove bases of DNA duplex. The non-covalent interactions of PFOS with SA and DNA alter their secondary conformations, with the physiological function of SA to transport Vitamin B2 being inhibited consequently. This work provides a useful experimental method for further studying the toxigenicity of PFCs.

The non-covalent interaction of brilliant red (BR) with lysozyme was investigated by the UV spectrometry, circular dichroism (CD) and isothermal titration calorimetry (ITC). The thermodynamic characterization of the interaction was performed and the assembly complexes were formed: lysozyme (BR) 17 at pH 2.03, lysozyme (BR) 15 at pH 3.25 and lysozyme (BR) 12 at pH 4.35, which corresponded to the physiological acidities. The ionic interaction induces a combination of multiple non-covalent bonds including hydrogen bond, hydrophobic interaction and van der Waals force. The two-step binding model of BR was found, in which one or two BR molecules entered the hydrophobic intracavity of lysozyme and the others bound to the hydrophilic outer surface of lysozyme. Moreover, BR binding resulted in change of the lysozyme conformation and inhibition of the lysozyme activity. The possible binding site and type of BR and the conformational transition of lysozyme were speculated and illustrated. This work provided a useful approach for study on enzyme toxicity of aromatic azo chemicals.