Preparation Of Novel Ginkgo Shells Bio-adsorbents For Cu²⁺ Removal

With the rapid development of industrialization and urbanization,environmental pollution has jeopardized human health and survival,especially water pollution.In the case of water pollution,the problem of heavy metal pollution is particularly serious.Such pollutants are generally characterized by high toxicity,difficulty in degradation,and easy enrichment,which makes heavy metal pollution in various water bodies increasingly serious.Unlike most organic pollutants,heavy metal ions cannot be degraded into harmless products,endangering the life of the organism.Faced with such problems,we urgently need to find ways to deal with heavy metal ions.Therefore,solving the problem of heavy metal wastewater pollution has become a common concern in the world.Among heavy metal ions,copper ions are widely used due to their low cost,and their pollution is relatively common.Among the many sewage treatment methods,the adsorption method is widely used in the treatment of heavy metal ion wastewater due to its advantages of simple operation,low cost,wide material,and no secondary pollution.As an emerging adsorption material,biomass materials have low cost and wide range of sources,which has attracted the attention of many researchers.The potential of replacing traditional sorbents for the treatment of toxic heavy metal ions in wastewater is huge.In this thesis,three different white-hull biomass-modified adsorbents were prepared by carbonization,oxidation and oxidative-amination dual-functionalization,and the ability to remove heavy metal ions was obtained by the dual-functional method for the first time as novel biosorbent.The paper analyzes the physicochemical properties and structure of the ginkgo shells before and after modification.Through the static adsorption experiment,the experiment of removing the heavy metal copper ions from the water by the ginkgo shells and its modified bio-sorbent is systematically studied and analyzed.Conditions:such as solution pH,initial concentration of pollutants,reaction temperature,adsorption time and other factors on the adsorption effect,and through the influence analysis and characterization methods to explore the adsorption mechanism of modified biosorbents on heavy metals.The main findings of this paper are as follows:?1?The ginkgo shells is used as the basic material,modified by three methods,combined with different characterization methods.The macroporous structure and surface oxygen-containing groups on the surface of the carbonized material increase;the oxidation causes the surface of the ginkgo shells to be destroyed and collapsed.The surface roughness of oxidized ginkgo shells?GK?is increased,and the number of functional groups is significantly increased;while the bifunctionalized ginkgo shells?GN?has excellent surface structure,large specific surface area,rich functional groups and stability.Thereby greatly increasing the adsorption performance of Cu²⁺in the wastewater;?2?Compared with raw material ginkgo shells?GR??8.62 mg/g?,carbonized ginkgo shells?GC??15.5 mg/g?and potassium permanganate-sulfate oxidized ginkgo shells?GK??31.8 mg/g?,the adsorption capacity of the double-functionalized ginkgo shells?GN??41.6 mg/g?was significantly increased,which was 4.83,2.68 and 1.31times,respectively.?3?Through calculation,it is found that the whole adsorption process conforms to the pseudo second-order kinetic model,indicating that the chemical adsorption of the functional group is a rate-limiting step.The Langmuir adsorption isotherm model yielded a maximum adsorption capacity was 47.6 mg/g of GN.Thermodynamic studies further show that the bio-sorbent prepared in this experiment was an endothermic process for the Cu²⁺adsorption process.The prepared bi-functional modified bio-sorbent has excellent chemical stability and reusability,and is a high-performance bio-sorbent for effectively treating heavy metal ion wastewater,and a new dual modification method can be opened.Widely used in different biological materials in nature,it provides a green and effective way to deal with waste biological materials,and also provides potential value for further industrial applications.