Precipitation dynamics of zinc sulfide multiscale agglomerates

Abstract

Homogeneous precipitation of zinc sulfide from thioacetamide decomposition in presence of zinc sulfate in acid solution results in the formation of four-scale agglomerates. We present here experimental results relative to the monitoring of several physicochemical (pH, electrical conductivity, concentration in sulfide ions, turbidity) and morphological (agglomerate shape and size) parameters throughout the precipitation process. From these parameters essential characteristics of the precipitation process can be determined, especially the supersaturation level and the precipitated product mass. From this information and with the help of microphotographs of samples withdrawn at different stages of the precipitation, it is possible to formulate a new mechanism of zinc sulfide precipitation. In particular, the nature of the different agglomeration scales is elucidated as well their succession in time.

Effect of hydraulic retention time on metal precipitation in sulfate reducing inverse fluidized bed reactors

“…This is an indication that the HRT was too short to allow all the Cd and Zn sulfide precipitates to grow and settle. Although the time scales of particle growth in metal sulfide precipitation has only been reported for a retention time of 200 min in chemical precipitator reactors, in contrast with a change of retention time from 24 to 9 h applied in this study (Fig. ), there is evidence that the growth of precipitates continues exponentially over the times studied in chemical precipitator reactors .…”

“…Although the time scales of particle growth in metal sulfide precipitation has only been reported for a retention time of 200 min in chemical precipitator reactors, in contrast with a change of retention time from 24 to 9 h applied in this study (Fig. ), there is evidence that the growth of precipitates continues exponentially over the times studied in chemical precipitator reactors . In addition, substances commonly present in bioreactors such as phosphate and bioproducts such as extracellular proteins, which are not present in chemical precipitator reactors, could enhance the agglomeration process.…”

“…Several authors have reported that the increase in particle size is mainly a consequence of aggregation or agglomeration (larger aggregates) of these fines . Agglomerates are, however, relatively fragile and so, the hydrodynamics in the bioreactor might play a crucial role in the size of the precipitates obtained …”

Photocatalytic Hydrogen Evolution from Water Splitting Using Core-Shell Structured Cu/ZnS/COF Composites

“…Another reason for this is the introduction of recombination sites (as recombination centers) and the light shading effect, which hinder light absorption by Cu 2+ ions and retard visible light absorption [12]. When the amount of substituent Cu 2+ exceeds the limit, the excessive dopant ions will cause a slight deviation from the blend phase structure due to a stacking disorder [31]. The photocatalytic stability can be assured by the repeated performance of using the recycled photocatalysts.…”

Low-Temperature Dehydrogenation of Ethanol on Atomically Dispersed Gold Supported on ZnZrOx

“…BET measurements find a large surface area for all ZrO 2 -containing samples, while pure ZnO made by the same method has a relatively low surface area (Table 1). This could be partially attributed to the difference in the precipitation rates of Zr and Zn salts, which will crucially affect the surface area and size of the precipitated particles [1][2] .…”