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  • Author: Joanna Grzechulska-Damszel x
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Joanna Grzechulska-Damszel and Antoni Morawski

Removal of organic dye in the hybrid photocatalysis/membrane processes system

The removal of azo dye Acid Red 18 in hybrid photocatalysis/membrane processes systems was investigated. The photocatalytic reactions were conducted in the reactor with photocatalyst suspended in the solution. The reaction solution was recirculated through the ultrafiltration system. A commercially available titanium dioxide (Aeroxide® P25, Degussa, Germany) was used as a photocatalyst. The solution after the photocatalytic/UF reaction was applied as the feed for the membrane distillation process. The changes of various parameters, including the concentration of the dye, pH and the conductivity of the solution, TOC and TDS content were analyzed during the process.

It was found that azo dye Acid Red 18 could be successfully decolourised in the hybrid photocatalysis/UF system. The catalyst particles were retained in the feed solution by means of the ultrafiltration membrane so the obtained permeate was free of TiO2. The application of ultrafiltration together with the photocatalytic process results in the separation of photocatalyst from the treated solution but does not give the complete removal of organic matter from the reaction mixture. Membrane distillation applied with the permeate after the photocatalysis/UF process as a feed gives a complete separation of TOC from the treated solution and the obtained product is practically pure water.

Open access

Joanna Grzechulska-Damszel and Antoni Morawski

Water purification using a novel reactor with the photoactive refill

The aim of the presented work was the removal of organic dye, Acid Red 18, from water using a novel reactor with the photoactive refill. Titanium dioxide was immobilized on the base material as a thin layer from the alcoholic suspension followed by thermal stabilization. The prepared coating exhibits high stability in repeated cycles of water treatment. The complete removal of colour was achieved in a relatively short time of 14 hours. The proposed reactor with the photoactive refill solves the problem of the necessity of the replacement of the reactor or parts of the reactor when the photocatalysts activity decreases. In the case of activity drop of the photocatalyst, only the photoactivve refill can be easily replaced.

Open access

Maja Rejek and Joanna Grzechulska-Damszel

Abstract

Pharmaceutical pollutants have been detected in many countries in surface and ground water after treatment in wastewater treatment plants. The presented studies concern the photocatalytic removal of one of SSRI antidepressants - sertraline from water using TiO2 photocatalyst. The process was conducted using two laboratory installations with periodic and flow reactors. Two forms of TiO2 was used in the photocatalytic reactions: suspended and supported onto a glass fabric. The studies shown that with increasing initial concentration of pharmaceutical, photoactivity decreases. For the initial concentration of 0.025 g/dm3, the best results – 94% removal – was achieved for the process conducted in the periodic reactor with TiO2 supported onto a glass fabric.

Open access

Marek Gryta, Agata Markowska-Szczupak, Joanna Grzechulska-Damszel, Justyna Bastrzyk and Marta Waszak

Abstract

In this work, the glycerol fermentation was carried out using Citrobacter freundii bacteria. The influence of glycerol and metabolites concentrations, and the pH changes on the efficiency of 1,3-propanediol production, during batch and fed-batch processes, was presented. The nanofiltration was used for the separation of obtained post-fermentation solutions. The resulted 1,3-PD solutions were significantly desalted, which may facilitate further downstream processes during 1,3-PD production.