Synthesis Of Organic Iron Compounds In Wastewater And Its Resource Utilization

With the rapid development of modern agriculture and industry, water pollution is more and more serious, especially the heavy metal and organic pollution of water, among which electroplating wastewater is one of the most representative wastewater. Electroplating wastewater is complex system with heavy metal ions, anionic surfactants, refractory organic matters and so many kinds of pollutants coexist. It is difficult to remove a variety of pollutants effectively and simultaneously. According to the idea of using waste treat waste, the heavy metal cations and organic matters in the electroplating wastewater were used to synthetic multiple organic LDHs by adding different quantity anionic surfactant and adjust different p H by means of the coprecipitation. Simultaneously the organic LDHs were used to sorption organic contaminants by its special organic phase structure between the layers to achieve the removal of a variety of pollutants and the self-purification of wastewater. Try to prepare organic and inorganic LDH at different pH to verify that organic LDH is easier to form than inorganic LDH.The factors, such as pH should be regulated and controlled to optimize the microstructures of multiple organic LDH, focusing on the microstructure control promoting the formation of multiple organic LDH, optimization the photocatalytic performance of the organic pollutants and the photocatalytic mechanisms. This study not only dealed with the recycling of heavy metal ions and organic matters in the electroplating waste water and obtained a kind of effective photocatalytic materials.Iron ions wastewater and surface wastewater are also the common wastewater. The toxicity to humans and animals of iron is very small, but when the concentration of iron in water is 0.1 0.3 mg/L, will affect the water’s sensory properties such as color, smell and taste. In this study, iron ions and DBS complex is prepared and its fenton effect and the mechanism are researched, probe the possibility that iron ion wastewater and surface wastewater can complex to prepare fenton reagent. The specific experiments are as follows: 1.Synthesis of organic layered double hydroxides（LDHs） in electroplating wastewater and application of the synthetic LDHsHeavy metal ions and organic contaminants can be effectively removed from electroplating wastewaters through self-assembly formation of multiple organic layered double hydroxides by adding simulation washing wastewater（SDBS）. The organic LDHs were characterized by XRD, EA, et al. The synthetic products were used to photocatalytic remove dye wastewater（Congo red） to survey the photocatalytic performance of organic LDHs and the NO selective catalytic reduction performance of C-LDO. The results show that the removal rate of heavy metal can reached 99% in some case. The removal of organic compounds can reach the maximum of 91%. The organic LDH materials displayed high photocatalytic activity under visible-light irradiation for Congo Red（CR） degradation. The decomposition efficiency of CR by organic LDH materials were higher than the inorganic LDHs. The NO selective catalytic reduction performance of C-LDO is also very good.The best one can completely remove NO at 300 ℃, and its maximum removal amount of NO reached 2.8 mmol/g. 2. The mechanism of competitory formation of organic and inorganic LDHOrganic and inorganic LDH are prepared at different pH respectively to probe their formation process and mechanism. It is proved that organic LDH is easier to form than inorganic LDH in low pH value. It is speculated that layer spacing, charge density and structure of LDH change when regulate pH value in organic LDH formation. With the increasing of pH, divalent metal ion increases, charge density decreases, and organic anion of interlayer reduces, interlayer opens, layer spacing increases. 3. Synthesis of organic iron complex and its application in the Fenton-like reactionFe²⁺/Fe³⁺-DBS complex were easily synthesized by the co-precipitation method at room temperature. The Fe²⁺/Fe³⁺-DBS complex were characterized by XRD, FT-IR, indicating that the Fe²⁺/Fe³⁺-DBS complex were synthesized successfully by this simple and rapid method. Fe²⁺-DBS complex can efficiently degradate of methyl orange in the Fenton-like reaction for many times, but lose it for degradating bisphenol A. Fe³⁺-DBS complex can also degradate of methyl orange in the Fenton-like reaction for many times, but its effect is less than Fe²⁺-DBS complex’s. Differently, Fe³⁺-DBS complex can efficiently degradate of bisphenol A in the Fenton-like reaction for many times. The reson of the complex’s loop fenton degradate organic is that it advantageously modify the redox potential of iron, allowingthe soluble complex to contribute in both the oxidative and reductive step of Fenton-like chemistry. This is thermodynamically allowed when redox potentials of iron complexes are in the range-324 mV< E° < 460 mV. The complex’s different effect of degradating different organics owing to the different oxidation reduction potential and the different mechanism of fenton.