| With the acceleration of urbanization,stone shorelines have become the mainstream of urban water environment.Compared with soil,rocky shorelines have the advantages of being easy to clean and manage.However,for the stony shoreline,it is difficult for plants to grow in the waterfront of the river,and the river's ecosystem is damaged to a certain extent;the lack of plants reduces the ornamental effect of the waterfront;due to the lack of blocking effects of the stony shoreline,Non-point source pollutants generated by rain washing the ground can easily enter rivers and cause pollution and ecological damage.In order to overcome these problems,a low-cost medium that can effectively fix plant roots to meet normal plant growth,and can filter and adsorb heavy metal ions washed away by rainwater to prevent them from entering the river's culture medium to replace traditional stone shores Lines are especially important.The purpose of this paper is to design a kind of planting blanket which can not only absorb heavy metal ions but also satisfy the normal growth of plants.The basic properties of the planting blanket under different acupuncture parameters and the adsorption properties of heavy metal ions Pb2+and Cu2+under different grafting conditions were discussed.In this project,the recovered waste fibers(polyester fiber 78 wt%;Cotton fiber 20 wt%;Other fibers 2 wt%)are carded into a web in a carding machine.Planting blanket substrate with an area density of 300-500 g/m2.Test the fracture strength,bursting performance,and air permeability to obtain a group with better comprehensive performance.The needling parameters are:needling depth 12mm,needling frequency 700 times/min.It was then used as the substrate for the planting blanket used in later experiments.Its breaking strength was 2.733 MPa,the burst specific strength was 447.805 g/N,and the air permeability was 760.80 mm/s.The aging performance of the selected group of planting blanket substrates was examined and the principle was explored.After 5 months outdoor aging,the breaking strength of the planting blankets remained at 86.24%,and the planting blankets showed excellent anti-aging properties.Adopting chemical grafting modification method gives the planting blanket good adsorption performance.The surface of the substrate is pretreated with a low-concentration sodium hydroxide solution to partially hydrolyze the ester groups of the polyester fibers in the substrate,and the cotton fibers have good alkali resistance without significant changes in properties,and then citric acid is used.It is a crosslinking agent,sodium hypophosphite is used as a catalyst,and ?-cyclodextrin is used as an adsorbent to graft-modify the substrate.The infrared adsorption,SEM,XRD,TG,ICP-OES and other methods were used to characterize the substrate adsorption performance and grafting effect The results showed that ?-cyclodextrin was successfully grafted onto the substrate.Orthogonal experiments show that when the concentration of sodium hydroxide is 4%;the concentration of ?-cyclodextrin is 2%;the baking temperature is 170?;when the baking time is 50 min,the adsorption of Pb2+and Cu2+is better,14.32 mg/g and 38.99 mg/g,respectively.The quasi-second-order kinetic model and Langmuir adsorption isotherm model can better describe the adsorption performance of planting blanketsBy comparing the basic properties of the planting blanket before and after grafting,it is found that the fracture strength of the modified planting blanket is still more than 98%compared with the previous one,and the moisture regain of the modified planting blanket is increased by 22.45%compared with that before the modification.After 10 s,the water contact angle changed from about 1250 to 0°.This shows that the modified planting blanket can not only support plant growth,but also provide plants with more water and make the plant grow better.In summary,the research results of this topic provide some guiding significance for the secondary use of waste textiles and environmental protection of urban rivers. |
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