| Popis: |
More than 1600 tones of polychlorinated biphenyls were produced in Poland in the 20th century. Despite their restriction and their ban in the 1970s, they are still present in the environment. Polychlorinated biphenyls are characterized by a high stability, which prevents them from being degraded. Due to the impact of PCBs on the environment they are classified as priority persistent organic pollutants. Adsorption is a simple, effective and fast technique for removing impurities. The aim of this work was to synthesis the halloysitecarbon composite and use it to remove chlorophene from aqueous solutions (a derivative of polychlorinated biphenyls). The morphology of halloysite and composite was investigated using a scanning electron microscope. The element composition was quantified with the X-ray microanalyser EDS. The parameters of the porous structure were determined with the ASAP volumetric adsorption analyzer. Infrared absorption spectroscopy (FTIR) spectra were recorded and studies of chlorophene adsorption on unmodified halloysite and halloysite-carbon composite material were carried out. Among other things, the effects of concentration and contact time on the adsorption process were investigated. The SEM images of the halloysite confirmed tubular structure and showed the presence of carbon particles on the halloysite surface in the case of the halloysite-carbon adsorbent. The EDS analysis confirmed the presence of carbon in the composite. Based on the FTIR spectrum, a difference in the structure of the halloysite-carbon adsorbent compared to unmodified halloysite was found. Removal efficiency of chlorophene from aqueous solutions determined by adsorption studies was about 95%, which means that halloysite-carbon composites are effective adsorbents for removal this compound from water. |
