Studies On The Application Of Nano-Materials And Technology In Water Treatment

The problem of water pollution is becoming more and more serious with the continuous development of global industry.Over the past few decades,various methods have been developed to purify water.Among them,adsorption is considered the most effective one among many water treatment methods because of its advantages such as simple operation,high versatility and low cost.With the development of the field of nano-materials,new types of nano-adsorption materials emerge as the times require.The advantages of high specific surface area,high adsorption capacity and easy functionalization of nanosorbent materials can provide sustainable solutions to existing wastewater treatment problems.Monitoring of contaminants in wastewater is essential to assess and avoid risks to human health.The traditional monitoring technology can not monitor the pollutants in the water environment in situ and in real time.The vigorous development of nanotechnology makes it possible to develop new affinity based recognition elements,which can overcome the limitations of traditional monitoring technology.The design and development of porous nano-materials can not only be used for rapid water purification,but also open up new ideas for the construction of sensitive,low-cost and convenient electronic components.We have successfully prepared a series of high performance nano-adsorption materials and deposited them on the gold chip of quartz crystal microbalance(QCM)sensor to achieve ultra-low concentration pollutant detection.The specific research content mainly includes the following four aspects:1.The concept of green sustainable chemistry has become one of the most valuable themes in the 21st century.Compared with synthetic materials,biomolecules have the advantages of wide source,renewable and low cost.Using biological wastes as precursors can not only reduce the cost of water purification,but also solve environmental problems.In this part of the work,we use soybean dregs as a precursor to prepare an efficient adsorbent for the removal of bisphenol S.By optimizing the experimental parameters,the selected adsorbent demonstrates large specific surface area as well as rich nitrogen-containing groups.Due to the synergistic effect of conjugation and hydrogen bonding,it shows excellent adsorption performance for bisphenol S.2.As the sewage contains a variety of acids,alkalis,salts and other corrosive substances,long-term immersion will cause varying degrees of damage to the adsorbents and affect the removal efficiency.For this reason,we believe that the development of new inorganic adsorbents can provide new ideas to overcome this challenge.In this part of the work,we prepare hierarchically porous boron nitride nanoribbon(HPBNN)via distributive pyrolysis.Experimental results show that:1)a hierarchically porous structure of HPBNN,which can capture bisphenol A effectively;2)good chemical stability,HPBNN maintained high porosity and superior bisphenol A clearance rate under harsh conditions;and 3)excellent practicability,the preparation and regeneration of HPBNN can be realized through simple process.In addition,the detection limit of QCM sensor based on HPBNN for bisphenol A is as low as 5 ppb.3.Among many factors affecting the performance of adsorbents,the affinity of adsorbents to pollutants is one of the most critical factors determining their performance.In this part of the work,we report an innovative multi-stage porous polymer,poly(1,3,5-tris[4-(diphenylamino)phenyl]benzene)(MPDPB).The theoretical pore size of MPDPB is 0.59 nm,which closely matches the physical size of bisphenol A.On the one hand,the conjugated structure of MPDPB can significantly enhance the van der Waals forces between it and bisphenol A.On the other hand,the theoretical pore size of MPDPB is 0.59 nm,which matches the physical size of bisphenol A.The matching of the two sizes can greatly increase the contact between bisphenol A and MPDPB pore walls,and further strengthen the van der Waals interaction between them.Theoretical calculations show that our designed polymer MPDPB has the highest binding energy for bisphenol A compared to cyclodextrin(CD)and activated carbon(AC)commonly used in water purification.The results show that the maximum adsorption capacity of MPDPB for bisphenol A was 826 mg/g.In addition,the detection limit of the sensor prepared by integrating MPDPB onto the QCM gold chip is as low as 0.1 ppb for bisphenol A.4.At present,many new types of nano-adsorbents have been developed for water treatment,such as AC,Metal-Organic Framework(MOF)and CD-based materials.However,most of the current adsorbents demonstrate low removal efficiency of plasticizer and are easy to produce secondary release.In this chapter,a multi-stage polymer,poly 1,3,5-triazine(4diphenylaminophenyl)triazine(MPTD)is synthesized in a dualsolvent system to remove bisphenol A from aqueous solution.The experimental results illustrate that the adsorption performance parameters of MPTD are much higher than those of the four commonly used ACs.Due to the good chemical stability of MPTD,it also exhibits ultra-high removal efficiency of bisphenol A under harsh conditions.We integrate MPTD into the gold chip of QCM sensor,and realize the detection of bisphenol A in ultra-low concentration aqueous solution(0.2 ppb),which provide reference value for convenient,low-cost,ultra-sensitive,real-time and on-site monitoring of water quality.