| The biotreated sewage is recognized as a good alternative water source due to its relatively low pollutant concentration and stable throughput.Advanced treatment is considered as an essential way for the reclamation and reuse of such effluent.The simultaneous removal of effluent organic matter(EfOM)and phosphate from biotreated sewage poses grave challenges for its advanced treatment and reuse.As an efficient advanced treatment alternative for wastewater,adsorption is widely used to achieve the reclamation and reuse of biotreated sewage.It is of great importance to develop a bifunctional hybrid adsorbent for the advanced treatment of biotreated sewage,which can simultaneously remove EfOM and phosphate from effluent.In this study,a novel bifunctional hybrid adsorbent named HFO-802 was successfully fabricated,by immobilizing nanoscale hydrated ferric oxides(HFO)into the aminated hyper-cross-linked polymeric adsorbent,NDA-802.P-nitrophenol(PNP)and phosphate were selected as model pollutants to test the performance of the resultant sorbents,while the effects of FeCl3 and NaOH concentration on the structure and property of HFO-802 were examined.Furthermore,the co-removal performance of the optimized HFO-802 for EfOM and phosphate was evaluated by using a practical biotreated sewage.Firstly,the role of FeCl3 concentration was examined by synthesizing four composites with various HFO loadings(5.4%,9.8%,12.3%and 16.7%in Fe mass respectively).These composites were denoted as HFO-802-X with X representing the Fe content.The experiments showed that the HFO content of the composites was elevated with the increase of FeCl3 concentration during synthesis.Varying HFO content significantly affected the pore structure and specific surface area of the composites,as well as the size and dispersity of HFO nanoparticles.The composite HFO-802-9.8 exhibited the best PNP and phosphate co-removal performance,while too high or too low HFO content was not appropriate.Furthermore,the influences of NaOH concentration were tested.Three different hybrids were fabricated for comparisons.The NaOH concentration mainly affected the size and dispersity of HFO particles,while the impacts on HFO content,pore structure and specific surface area of the composites turned out to be limited.Increasing NaOH concentration within a certain range was conducive to improve the dispersity and decrease the particle size of nanosized HFO,thereby enhancing the property of phosphate uptake.The concentration of NaOH did not show notable effect on the adsorption of PNP.Based on the results above,the optimum technological parameter(5%FeCl3 + 10%NaOH)was selected to fabricate HFO-802.The co-removal performance for EfOM and phosphate from practical biotreated sewage was evaluated.Fixed-bed adsorption experiments demonstrated that the fresh HFO-802 could dispose about 450 bed volume(BV)biotreated sewage,with the quality of effluent conforming to one-class A criteria of GB18918-2002 and one-class criteria of GB8978-1996.More attractively,the HFO-802 after adsorption could be efficiently regenerated by NaOH and NaCl binary solution and the desorption efficiencies of EfOM and phosphate were up to 90.8%and 97.9%,respectively.Cyclic adsorption-regeneration runs indicated that the adsorption property of HFO-802 was stable,which could realize repeated use with constant adsorption capacity.On the basis of structural tuning and performance optimization of the novel bifunctional hybid adsorbent,this study developed a new technique employing environmental functional material for advanced treatment of biotreated sewage and further expanded the application scope of nanocomposite adsorbent.The results reported herein could offer significant guidance for the development of advanced treatment technique for the biotreated sewage.Furthermore,this study was of great guiding significance to the design optimization of other new HFO-oriented nanocomposite adsorbents and the development of advanced treatment technology for biotreated sewage. |
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