Study On The Adsorption Of Heavy Metal Ni²⁺ By Modified Maize Pulp

The pollution of heavy metal ions has been widely concerned and the methods of removing heavy metal ions have been constantly updated and improved.In recent years,the preparation of cheap and efficient adsorbent has become the focus of research.The low cost of agricultural and forestry waste has attracted the attention of many researchers,driven by the concept of abolishing waste.In this paper,the corn pulp of agricultural forest waste is used.Introduce fenton,sodium hydroxide and citric acid modification and study the adsorption of heavy metal Ni²⁺in the modified corn pulp.The results are as follows:（1）In the corn pulp adsorbent modified scheme comparison of the process,the use of hydrochloric acid,sodium hydroxide,fenton modifies corn pulp powder separately,comparing the effect of reagent combination and the system of"fenton+sodium hydroxide"modified corn flesh powder was optimized.After the pretreatment of "fenton+sodium hydroxide",the surface structure of the corn pulp powder became loose,the surface fold was obvious and the surface area increased.After the treatment of citric acid,the carboxyl content increased,and the number of adsorbent binding sites was increased and the adsorption capacity of maize pulp adsorbent was further strengthened.（2）In the stage of the corn pulp adsorbent modified scheme optimization,explores the effect of the fenton reaction at the bottom of the water quantity,the proportion of fenton,corn pulp sodium hydroxide of solid-liquid ratio and the reaction time of the citric acid on the adsorbent adsorption Ni²⁺.It was found that the effect of corn pulp powder added 50 ml bottom water under fenton modification is better.As the proportion of fenton and corn pulp sodium hydroxide solid-liquid ratio has increased,corn pulp adsorbent adsorption capacity increase.However,when the fenton ratio was more than1:15,the effect of maize pulp adsorbent on Ni²⁺adsorption capacity decreased significantly.The adsorption capacity of maize pulp adsorbent on Ni²⁺also began to decrease significantly when the solid-liquid ratio of sodium hydroxide was more than1:15.The control of reaction time of citric acid directly affected the modification effect of the functional group.The experimental results show that the optimal reaction time of citric acid reaction is 1.5h.（3）The adsorption process of adsorbent Ni²⁺adsorbent on maize pulp was shown:it was found that the most suitable pH of the adsorbent of corn pulp adsorbent Ni²⁺was6.Under the condition of 100mL20mg/L,0.2g was the optimal dosage for the corn-pulp adsorbent.When the temperature is 25℃,the adsorption of corn pulp adsorbent to the Ni²⁺adsorption efficiency and the removal rate to achieve the optimal.When the initial ion concentration is 20mg/L,the removal rate reaches 84.46%,and then the removal rate gradually decreases with the concentration.In ion coexist in use in the analysis of heavy metal ions for chromium ion,it was found that in the corn pulp adsorbent of low adding amount（<2 g/L）when the chromium ion coexist has certain influence,as dosing quantity has increased,effect is not obvious.In addition experiment on adsorbent adsorption dynamics,thermodynamics is simulated in the process of Ni²⁺,found that modified corn pulp adsorption Ni²⁺on the kinetics of more accurate dynamics model of the secondary and conforms to the Langmuir adsorption isotherm on thermodynamic model.According to the thermodynamic simulation results,the maximum adsorption capacity of adsorbent was 17.24mg/g.（4）In the modified corn pulp desorption relapsed experiments found that in the case of using hydrochloric acid as the desorption agent,the optimum concentration of desorption agent is 0.15 mol/L and the optimum temperature for desorption is30℃.The results of several experiments showed that the desorption rate of hydrochloric acid to the modified maize pulp adsorption Ni²⁺could reach more than90%,and the adsorption regeneration rate could reach about 85%,and the adsorption material had certain desorption and resorption capacity.