Study On Preparation And Adsorption Capability Of The Modified Banana Peel Adsorbent

In this paper, agricultural waster banana peel as raw materials was modified with chemical modification for preparation of the adsorbent. Then the modified banana peel adsorbent was carbonized into activated carbon. All kinds of analysis methods,as the ammonia adsorption experiment, the specific surface area test, FT-IR, SEM were used to study the physical structure and chemical properties.Through the laboratory experiment, the adsorption capacity of modified adsorbent was studied under a variety of parameters. Adsorption column that had modified banana peel adsorbent and activated carbon was made to study on the removal of dynamic water condition.The experimental results are as follows:1. The best preparation condition and structure characterization of the modified adsorbent and activated carbon.The banana peel was modified adsorbent,whose the best modifier is Na OH, and it is best to 0.2mo L/L, the ratio of solid to liquid is 10g/L, modification time is 20 min. Under 850℃ the modified banana peel adsorbent can be prepared with activated carbon of high specific surface area, 1534 m2/g by blending with KOH. The surface structure of modified banana peel adsorbent and activated carbon were fold and porous by SEM. And the diameters of activated carbon pores were in between 2.1-2.7, and this pores achieved 92.8% in the total pores. Many functional groups were found on surface, and can inprove the adsorption performance of modified banana peel adsorbent and activated carbon.2. The effect of reaction conditions(dosing quantity, adsorption time, p H)to absorption, when modification adsorbent deals with ammonia nitrogen, Cd2+, Pb2+, Cu2+, and fenpropathrin. Research shows that p H value increases as adsorption rate increase. When the modified banana peel adsorbent and activated carbon removed 6mg/L ammonia water, the optimal dosage were 0.2g/50 m L, 0.4g/50 m L, adsorption equilibrium time were 13 min, 45 min and saturated adsorption capacity reached 7.4787mg/g, 2.001mg/g respectively. When the modified banana peel adsorbent and activated carbon removed 100mg/L Cd2+ or Pb2+ or Cu2+ water, the optimal dosage were 0.2g/50 m L and 0.1 g/50 m L, adsorption equilibrium time were45 min, 20 min and saturated adsorption capacity reached 79.5234mg/g, 98.1351mg/g, 69.8760 mg/g and 136.7754mg/g, 160.0214mg/g, 88.5461mg/g respectively. When the modified banana peel adsorbent and activated carbon removed 100ug/L fenpropathrin water, the optimal dosage were 100ug/50 m L, 60ug/50 m L, adsorption equilibrium time were 60 min, 50 min and saturated adsorption capacity reached 59.7372 ug/g, 188.9024 ug/g respectively.3. Isothermal adsorption research. Both adsorption isotherms of the modified banana peel adsorbent and activated carbon seal with ammonia nitrogen and fenpropathrin were in line with Langmuir and Freundlich adsorption isotherm. The adsorbents processing of ammonia nitrogen and fenpropathrin adsorption is between single molecule layer and polymolecular layer. The uniformity of adsorption surface of adsorbent has certain influence with adsorption process.According to the Freundlich adsorption model, modified banana peel adsorbent for Cd2+, Pb2+, Cu2+ probably belonged to between monolayer adsorption and multilayer adsorption, and activated carbon for Cd2+, Pb2+, Cu2+ belonged to monolayer adsorption.4. Cd2+ had the dominant position in the the competitive adsorption of Cd2+ and ammonia nitrogen, or Cd2+ and fenpropathrin. When the surface of the modified banana peel adsorbent and activated carbon was occupied by Cd2+, ammonia nitrogen and fenpropathrin adsorption would be reduced. In the adsorption column experiment, the water sample that is twice the national standard pollutant concentration limit was processed by adsorption column, removal rate of Ammonia and heavy metal were more than 99%, removal rate of fenpropathrin was 96.9%.The study provided a new method with high efficiency and low cost for treating the waste crop banana peel and broaden the study methods that the waste crop banana peel was made water treatment adsorbent.