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A non-optimised treatment of wastewaters containing organic and biological substances is very often accompanied by an accidental emanation of hydrogen sulphide H2S and therefore leads (i) to an undesirable odour in the vicinity of water treatment plants, and (ii) to a potential hazard for the neighbouring population. Fast, sensitive and reliable monitoring devices hence of significant importance. Chalogenide and chalcohalide glass are new promising membrane material for detection of heavy metal ions and toxic anions and particularly well adapted for continuous in situ monitoring and industrial process control. In the present paper, we will discuss analytical characteristics of new chalcogenide glass chemical sensors for detection of S2- and dissolved H2S, which slow reliable process control to be carried out at natural pH of wastewaters.

State-of-the-art neutron and X-ray diffraction measurements have been performed to provide a definitive picture of the intermediate-and short-range structure of P x Se 1-x glasses spanning the two glass regions, x = 0.025 -0.54 and 0.64 -0.84. Liquid P 4 Se 3 and amorphous red P and Se were also measured. Detailed information was obtained about the development with increasing phosphorous concentration of intermediate-range order on the length scale around 10 Å, based on the behavior of the first sharp diffraction peak. Attention is also paid to the feature in the structure factor at 7.5 Å -1 , identified in earlier numerical simulations, provides further evidence of the existence of molecular units. The real-space transforms yield a reliable statistical picture of the changing short-range order as x increases, using the information about types and concentrations of local structural units provided by previous NMR measurements to interpret the trends observed.