Report On Electrochemistry-Adsorption-Precitation Method In Treating Electroplating Wastewater And Application Studies

Study of recent years reveals that Natural Clay Minerals have relatively strong adsorbability and ion exchangeability ,and their usage in environmental protection is getting wider. Among them, Montmorillonite has quite good preferential adsorbability to Cr3+ and Cr6+; Kaolinite and Illite have affinities to Cr3+ and Pb2+; Clay mineral is most suitable in treating cationic dye wastewater by using adsorption-flocculation method; as for Modified Clay Minerals, Hydroxy laluminium-Organic Pillar Supporting Bentonite can reduce up to 95% of phenol in processing phenolic wastewater; CPC-OH-AL-Bentonite and LA-Bentonite in treating wastewater containing chlorophenic acid and benzopyrene, saturated adsorption capacity of monolayer molecules can reach 6.1g/g and 12.3g/g; the list goes on and on ...Rectonite is Clay Mineral which main composition is Aluminosilicate, its molecular structure possesses quite strong adsorbability and cationic exchangeability, moreover, China is very rich in Rectorite resources ,so related research on the application of Rectorite in treating electroplating wastewater is of great importance.The preparation methods of Rectorite Cross-Linked is described; the effect of the conditions of preparing Rectorite Cross-Linked on the adsorption of elecoroplting wastewater containing Chromium is studied. The experiments indicate: The adsorption efficiency of Cross Linking Rectonite to Cr6+ goes up with the concentration of Rectonite suspension increases and with the applied Fe Cross Linker increases as well; it goes down while the temperature of producing Cross Linking Rectonite rises ; meanwhile, the time of cross linking reaction and the pH of Rectorite suspension is another influence on the adsorption efficiency of Cross Linking Rectorite. By way of orthogonal experiments our study fixed the better conditions of preparing Rectorite Cross-Linked to the adsorption efficiency to Cr6+: Rectorite suspension pH=6,the weight ratio of Fe Cross Linker to Rectorite is 4%, cross linking reaction temperature 35 . Meanwhile the effect of pH , temperature and concentration of beginning on the adsorption is discussed. The optimum conditions evolved from experiments are; wastewater pH<2, adsorption equilibrium time t=3h, Cr6+ concentration of wastewater Co<40mg/L, and the adsorbing process practically matches Freundlich adsorption isotherm, G=0.895Ce0.272. This report combined electrochemical reactions and adsorbing reactions in terms of theory, and carried out theoretical analysis and calculations about the new technology adopted to treat wastewater from electroplating industry. The experiments indicate: adding right amount of reductive TX and Cross Linking Rectorite can remove as much as 99.51% of Cr6+ from low concentration wastewater (40mg/L). Since this technology was adopted to treat wastewater of electroplating factories, plus using electrochemical protection method and proper welding technology to prevent the equipments from partial corrosion , pitting corrosion and inter-crystallinecorrosion, it has achieved noticeable effects in combating wastewater contamination and equipment corrosion. This research does have broad prospects of practical application.