Preparation Of Seaweed-based Photocatalysts And Its Adsorption And Photodegradation Ability On Sea Surface Oil

With the acceleration of global economic integration process,the demanding for petrochemical products of human has been increasing,while related industries such as offshore oil transportation and offshore oil resources development are also developing rapidly.However,the resulting oil leakage problem is intensifying,which would do extremely harm to ecological environment and health of human beings.At present,there are many treatment measures for oil pollution,and the adsorption and photocatalytic methods have attracted extensive attention due to their excellent performance.In this study,we demonstrate that activated kelp biochar with good porosity and wide specific surface area by using the abundant and available local kelp is first-time successfully prepared through pyrolysis at 800? and then by chemical activation method using KOH as an activating agent,which can be used as an excellent adsorbent and a natural carrier for photocatalysts with a higher value-added use of kelp biomass.And novel Bi₂MoO₆/kelp biochar nanocomposite is fabricated by a combination of pyrolysis and solvothermal method,which can effectively solve the agglomeration between photocatalyst molecules,the non-degradability of the carrier,the low recycling rate,and the high photogenerated electron-hole rate and the low carrier mobility.The synthesized sample is characterized by BET,XRD,FT-IR,SEM and UV-vis,and the adsorption and degradation performance of petroleum hydrocarbon pollutants are also studied.1.The experimental program for pyrolysis of kelp biochar at the following conditions:carbonization at 800? in a tube furnace for 3 h under N₂ atmosphere.SEM and BET data analysis shows that the specific surface area of kelp materias after carbonization have increased from 90.561 m²/g to 511.934 m²/g,and the modified kelp charcoal has high carbon content and abundant pore structure,which is beneficial to the adsorption of petroleum pollutants.2.Oil pollution of adsorption experiments show that the adsorption rate of oil pollution by modified kelp carbon can reach 64.70%,probably due to its high specific surface area?507.177 m²/g?and abundant functional groups?such as,-OH,=CH,etc.?.And the photocatalytic experiments show that kelp charcoal itself has a certain photocatalytic ability probably due to the existence of a large amount of transition metal oxides?more than 698.1 mg/kg?,and XRD results also prove the presence of Fe₂O₃,Mn₅O₈ and other metals oxides.Meanwhile,the rich amorphous carbon content may promote photocatalytic performance.3.The composite photocatalyst with different loading?Bi₂MoO₆:modified kelp charcoal?is successfully prepared by solvothermal method with 800? anoxic carbonization and KOH modified kelp charcoal as carrier materials.The best performance obtained by a composite photocatalyst with a loading of 0.25 is selected as the experimental sample in the later experiments by pre-experiment and BET data?The specific surface area and pore volume are 210.918 m²/g and 0.2449 cm³/g,respectively.4.Oil pollution adsorption experiments are carried out as follows:the dosage of composite photocatalyst is 0.03 g,the initial concentration of oil pollution is 20 g/L,and it is stirred for 3 h under dark conditions.And with the temperature at 25°C,the removal rate of oil pollution can reach 70.08%?...