Functionalization Of Solid Wastes And Application In Pollution Treatment

The rapid development of industry and agriculture has greatly improved daily production and lifestyles,and also produced a large amount of solid wastes.Accumulating or discharging solid waste into the environment can easily endanger the ecological environment and human health.Therefore,the reasonable disposal and utilization of these solid wastes has become a hot spot in environmental research in recent years.Among them,biochar produced by the high-temperature anoxic pyrolysis of organic solid wastes,and red mud produced during the aluminum smelting process by the Bayer process,have been widely used in the environment treatment due to their large output and high utilization value.In terms of water treatment,red mud and biochar are used for the repair and treatment of various types of sewage,but these methods have some defects,such as complex material processing,high cost,low use efficiency,and easy to cause secondary pollution.The shortcomings severely restrict their large-scale application in environmental treatment.Therefore,it is urgent to develop a low-cost,simple process,and high-efficiency technology and method for the treatment of biochar and red mud,and use it for environmental pollution prevention and control.Based on the current methods of processing and applying biochar and red mud,we develop two new materials using biochar and red mud as raw materials,and use them for environmental pollution prevention and control.The main contents of this thesis are as follows:(1)Preparation and application of biochar-based materials showing lightswitchable wettability.A light-switchable herbicide nano safener(LHNS)with rough micro-nano structure and high hydrophobicity is prepared using biochar(BC),TiO2 and hydrogen silicone oil(HSO).LHNS can endow crop leaves with a hydrophobic surface,decrease the adhesion of glyphosate(Gly)and thus be used as a good safener of Gly.Upon UV irradiation,LHNS is transformed to hydrophilic HL-LHNS due to the photocatalytic effect of TiO2.The obtained HL-LHNS can endow crop leaves with a hydrophilic surface,increase the absorption of urea,and thus promote the growth of crops.Interestingly,IR irradiation can transform the HL-LHNS to hydrophobic HBLHNS which can also be used as Gly safener.As such,the wettability of LHNS-treated crops leaves can be easily adjusted by UV or IR light,showing good recyclability.This work provides a new method for economical and efficient use of biochar,and also opens up a new idea of practical and safe protection of plant leaves.(2)Red mud functionalization and its application in the treatment of acidic dyeing wastewater.Using two solid wastes of red mud and corn stalks as raw materials,a magnetic biochar material is prepared.The material has a porous structure and contains a large amount of alkaline substances,showing strong adsorption capacity for dye molecules and acid neutralization ability.Therefore,it shows excellent performance in the treatment of acidic dyeing wastewater.In addition,the material can be collected by the method of magnetic recovery,and the treated wastewater has good biological safety.This work applies solid waste to industrial sewage treatment,achieving the dual goals of waste recycling and pollution control,and embodies the concept of "using waste to treat waste".