CarboTech (Germany)

Abstract Eine Belastung von Trinkwasser mit PFAS ist unerwünscht und gesundheitsgefährdend. Anhand eines Anwendungsbeispiels im Rohwasserpumpwerk Creglingen wird mithilfe einer vergleichenden Untersuchung zur Rückhaltung von Metaboliden des Pflanzenschutzmittels Chloridazon die Trinkwasseraufbereitung unter Bezugnahme auf PFAS dargestellt. Dabei wird die Filterleistung von Aktivkohle auf Kokosnussbasis mit Aktivkohle auf Steinkohlebasis verglichen.

Abstract The process-based evaluation of adsorbents is considered the most foolproof method with respect to a particular application, as it provides data about the separation effectiveness in authentic operating conditions. This paper presents empirically obtained performance results of the kinetically-controlled air separation on multiple carbon molecular sieves carried out in a twin-bed pressure swing adsorption unit. The effect of adsorbent pellet size on nitrogen productivity and air demand is studied at different product purity levels (10–10,000 ppm O2 of the residual oxygen concentration), operating temperatures (25–45 °C), and half-cycle times (35–70 s). The selected process conditions correspond to the majority of practical applications. Guidelines for the suitable particle size depending on the desired nitrogen purity are given.

Reactions of Disodium Dicyanodithioacetate and Sodium Dicyanothioacetamides with Derivatives of γ‐Bromocrotonic AcidThe dicyanodithioacetate 3 reacts with the derivatives of γ‐bromocrotonic acid 4a and 4b to give the thieno‐[2,3‐b]thiophenes 5a and 5b. 3 can also be alkylated successively with two different alkylating reagents. In this way the compounds 5c, 6a, and 6b are prepared. Reactions of the dicyanothioacetamides 8a and 8b with 4a and 4b yield the thiazolidines 9a–d.