Microstructured adsorbent material: silica dioxide - polyaniline for retaining aniline and chromium ions

The alkaline etch (KOH) of silicon is one of the well-known methods for obtaining integrated circuits on silicon (chips), but the resulted alkaline solution of potassium silicate is a waste. This paper presents a recovery method of potassium silicate alkaline solution by its transformation in a microstructured adsorbent material for aromatic amine derivatives and chromium ions. The micro-structured adsorbent material is obtained by mixing the potassium silicate alkaline solution with an acidic solution of polyaniline, which is obtained by the oxidation of aniline hydrochloride with potassium persulphate. The silica-polyaniline (SiO2-PANI) micro-structured material was characterized in terms of morphology (SEM, HR-SEM), structure (EDAX, FTIR) and its process performances (adsorption of anilines and chromium ions). The results show that silicon for electronic use can be fully exploited, both as integrated circuit and as adsorbent material for aniline or chromium ions, presenting economical, technical and environment protection benefits.