Preparation Of Novel Adsorbent And Its Adsorption And Purification Of Heavy Metal Ions In Solution

Due to the rapid development of China's social economy and the acceleration of the process of industrialization,more and more heavy metal wastewater without standard treatment is discharged into water bodies,causing serious environmental pollution problems.Heavy metal ions are potential highly toxic pollutant and difficult to degrade,which has a wide range of sources and is easy to accumulate in organisms,posing a serious threat to the living environment and human health of various organisms.In recent years,heavy metal pollution has become increasingly severe,leading to frequent heavy metal pollution events in water.How to effectively remove heavy metal ions in water has become a social problem that cannot be ignored.The traditional methods of heavy metal ions removal include chemical precipitation,biological method and ion exchange method.Among many methods,adsorption method has become a research hotspot in recent years due to its advantages such as high adsorption capacity,wide application range,easy operation and environmental friendliness.Among the numerous adsorbents,nanoflower-like organic silica?NFOS?,due to its large specific surface area,surface easy modification and good chemical stability and other advantages,which is the current research focus as an adsorbent.However,adsorption capacity of heavy metal ions for NFOS is small,in order to improve its adsorption ability of lead ions,organic silica is modified with norepinephrine?NE-NFOS?,which has large aperture and entrance and is favorable for the lead ions to spread the interior of the silicone channel.Moreover,catechins and amino of norepinephrine and lead ions can react,which improves the adsorption effect of lead ions further.NFOS was synthesized by hydrothermal method in this paper,and norepinephrine was grafted onto its surface to prepare a new adsorbent NE-NFOS.The surface morphology and pore volume of NE-NFOS were characterized by scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,specific surface area and porosity analyzer?BET?and Fourier infrared spectroscopy?FTIR?.Taking heavy metal ion Pb²⁺as the research object,the adsorption performance of NE-NFOS on Pb²⁺was studied from the adsorption isotherm,adsorption kinetics and other aspects through the adsorption experiment,and the influence of different parameters such as solution pH,K⁺,Na⁺,Ca²⁺,Mg²⁺concentration on the adsorption behavior was further investigated.The SEM and TEM images of NE-NFOS show that there are abundant pore structures on the surface of the adsorbent.The cumulative adsorption pore volume,specific surface area and pore diameter of BJH were0.28 cm³/g,132 m²/g and 3.08 nm,respectively.The adsorption and purification experiments of lead ions in solution showed that the adsorption capacity of NE-NFOS increased significantly compared with that no modification.When the pH value was 6.0,the saturated adsorption capacity was 160mg/g.Freundlich model was more suitable to describe the adsorption behavior of NE-NFOS on Pb²⁺.The equilibrium adsorption capacity was greatly affected by the initial pH value of the solution,but was weakly affected by the plasma concentrations of K⁺,Na⁺,Ca²⁺,Mg²⁺concentration.After repeated use for 4 times,the removal efficiency of adsorbent for Pb²⁺ion was greater than 79%of its initial value.The adsorption test results showed that NE-NFOS is a kind of adsorbent with good adsorption performance and can be used for the removal of lead ions.In order to reduce the cost of adsorption materials and simplify the synthesis steps,wheat bran biochar was prepared by pyrolysis of wheat bran,which was used as an adsorption material and the adsorption and purification performance of chromium ions in the solution was studied.Surface morphology and pore volume of wheat bran biochar were characterized by SEM,BET and FT-IR.Taking heavy metal ion chromium ion as the research object,the adsorption performance of wheat bran biochar on chromium ion was studied from the aspects of adsorption isotherm and adsorption kinetics through the adsorption experiment,and the influence of different parameters such as solution pH,Na⁺,K⁺ion concentration on the adsorption behavior was further investigated.SEM figure shows that the surface of wheat bran biochar presents a hollow porous granular structure,with irregular distribution of pore diameter and texture,which increases its surface area and is conducive to its adsorption of chromium ions.The cumulative adsorption pore volume,specific surface area and pore diameter of BJH were 0.08 cm³/g,80 m²/g and 3.08nm,respectively.The adsorption and purification experiments of chromium ions in the solution showed that the adsorption capacity of wheat bran biochar was significantly increased compared with that no pyrolysis.When the pH value was 2.0,the saturated adsorption capacity was 67 mg/g.In addition,the equilibrium adsorption capacity was significantly affected by the initial solution pH value,but was weakly affected by the Na⁺and K⁺plasma concentrations.The results of adsorption test showed that wheat bran biochar had a good prospect in removing chromium ions from wastewater.