الفهرس 
Introduction and Literature SurveyOnly 14 pages are availabe for public view
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Abstract
The presence of heavy metals and anions discharged into water streams as a result of industrial activities is becoming an ever-increasing challenge to ensuring safe and clean aquatic environment. Therefore, it is necessary to detect and determine the levels of heavy metals and anions in wastewater. As a result, the focus of this research was on developing suitable, simple and cost-effective sensors that could detect and remove these metal ions with high selectivity and sensitivity. In this study we report on novel optical chemosensors containing benzothiazole moeity namely; 4-Chloro-2-(4-methyl-benzothiazol-2-ylazo)-phenol (CMBTAP), 1-(6-Chloro-benzothiazol-2-ylazo)-naphthalen-2-ol (CBAN) and 2-(6-Chloro-benzothiazol-2- yl azo)-4-methyl-phenol (CBAMP) which were synthesized and characterized by FT-IR, 1H-NMR, 13C-NMR and mass spectrometry. The solvatochromic behavior of benzothiazole dyes was explored in different solvents of various polarities to explore the active fluorescent tautomer and the photophysical parameters have been measured. The colorimetric and optical sensing properties of CMBTAP, CBAN and CBAMP toward different metal ions and anions were investigated by the naked eye as well as UV-Vis and fluorescence spectroscopy. These chemosensors show a powerful sensing ability with high sensitivity and selectivity toward some of the studied metal ions as well as toward CO32- and CN- over other anions. The binding constants (Kb) and stoichiometry of the formed metal ions–sensor complexes were determined by the Benesi–Hildebrand and Job’s plots, respectively. The detection limits for Fe3+, Cu2+ and Co2+ by CMBTAP, CBAN and CBAMP were found to be lowest than other metal ions used (2.5 x10-5, 8.4 x10-7 and 6.4x10-7 M), respectively. Stern-Volmer quenching constants Abstract & Key words (Ksv) were found to be highest for Cu2+ at 29.8 x104 M-1 as well as for CO32- at 8.5 x105 M-1 for CBAN chemosensor. The results reveal that CMBTAP chemosensor is low efficiency for sensing of metal ions compared to other chemosensors. To improvement the sensitivity and selectivity of CMBTAP, based on mesoporous TiO2 and amino-functionalized mesoporous TiO2, the fluorescent chromophore CMBTAP has been anchored into the amino-functionalized mesoporous TiO2 synthesized using pluornic123 and CTAB as templates, to yield CMBTAP-M-TiO2 (1) and CMBTAP-M-TiO2 (2), respectively. The designed nanosensors were characterized by FT-IR, transmission electron microscopy, nitrogen adsorption–desorption isotherms, X-ray diffraction, and thermogravimetric analyses. The colorimetric, and optical sensing behavior of nanosensor analogues toward different metal ions were explored using naked-eye observations, steady-state absorption and emission techniques. Significant changes in colors, in the absorption and emission spectra were observed. The action of these nanosensors is reversible where on adding EDTA to the formed complexes, the original absorption and emission spectra of the free sensors are restored demonstrating that the chelation process is reversible. In comparison with CMBTAP, the results revealed that the nanosensors exhibited a stronger binding affinity, selectivity, sensitivity, and lower LODs for the studied metal ions, implying that the sensing efficiency of CMBTAP is improved after loading onto the nanostructured TiO2. Thus, we have successfully converted the hazardous azo dyes into an environmentally safe optical sensor for detection of toxic metal ions in wastewater with high sensitivity. Furthermore, the biological chemosensing applications of the chemosensors CMBTAP, CBAN and CBAMP to Fe3+, Cu2+ and Co2+ ions respectively, were demonstrated for fluorescence imaging experiments in Abstract & Key words living cells. The fluorescence images for CMBTAP and CBAN grew weak brighter with Fe3+ and Cu2+ ions, respectively, compared to that recorded with the free CMBTAP and CBAN. Additionally, the fluorescence image of CBAMP grew brighter with Co2+ compared to that recorded with the free CBAMP. Supporting that the CMBTAP, CBAN and CBAMP chemosensors is an effective fluorescent biosensor for Fe3+, Cu2+ and Co2+ metal ions respectively. The inhibition effect of three dyes CMBTAP, CBAN and CBAMP as well as its synergistic effect with KI on the corrosion of carbon steel in 1.0 M HCl solution was studied by using weight loss, potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS). The inhibition efficiency increases with increasing the concentration of the azo dyes. Additionally, the inhibition efficiency increased further with the presence of KI. The adsorption of inhibitors on the carbon steel surface obeys the Langmuir adsorption isotherm. The polarization studies indicate that the investigated compounds are mixed type inhibitors. The carbon steel surface morphology was evaluated using a scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis.