Nanocomposites and nanomaterials

Hybrid composites for the removal of Rhodamine 6G dye from aqueous solution 

Kyshkarova V.V. 1,2, Vaclavikova M.1 Melnyk I.V.1

1 Institute of Geotechnics, Slovak Academy of Sciences, 45 Watsonova Street,
Košice 04001, Slovakia
E-mail: kyshkarova@saske.sk
2 Technical University of Košice, 9 Letná, Košice 04200, Slovakia

Sorbents are widely used to removal some classes of chemical pollutants from industrial water, particularly those are scarcely destroyed in conventional wastewater treatment plants. Dyes are serious issues because they are discharged into wastewater from several types of industries (textile finishing and dye manufacturing). The adsorption process offers alternative for the treatment of contaminated water, at the expense of low-cost and high performance adsorbents. 
Three composites with various ratios silica/polymer 5/1, 10/1, and 20/1 were synthesized by one-step sol-gel method. For inorganic precursor part produce tetraethyl orthosilicate (TEOS) was used as precursor and as an organic one - styrene-acrylic polymer Tubifast 4010 ®. The composition and structure of new composites were investigated by the number of physico-chemical methods. Infrared spectroscopy confirmed the formation of Si-O-Si bonds, the presence of polymer in the silica matrix, and the interaction between organic and inorganic components as well as the presence of functional groups owned by the composites. It was established that the synthesized materials had acid groups on the surface in the range of 1.44 – 1.76 mmol/g, the values of isoelectric point are at pH = 2.6 – 2.8, high specific surface area (399-548 m2/g). 
The composites were tested as adsorbents for uptake of cationic Rhodamine 6G (R6G) dye from water solutions. The investigation of adsorption experiments were carried out as a function of pH, contact time and initial dye concentration. The results demonstrated that the hybrid composites are efficient adsorbents for R6G removal.
This research is supported by the APVV-19-0302, DoktoGrant (APP0141), and VEGA 2/0156/19 projects.