1. Materials and Chemical Engineering Group, School of Engineering; University of Aberdeen; Aberdeen AB24 3UE UK
2. Surface Chemistry and Catalysis Group, School of Natural and Computing Sciences; University of Aberdeen; Aberdeen AB24 3UE UK
3. Water Research Institute, National Research Council (CNR-IRSA); Via Salaria km 29.300 C.P. 10 00015 Monterotondo (RM) Italy
4. Department of Plant and Soil Science; University of Aberdeen, Cruickshank Building; St. Machar Drive Aberdeen AB24 3UU UK