Study On Key Technologies Of Separation And Recovery Of Heavy Metal Cr(?) From Water Body By Chitosan Stabilized Nano Iron Modified Biochar

Biochar is an excellent environmental functional material and has high removal rate for heavy metals in water.The performance of biochar modified by nano iron has been greatly improved,but the stability is not good.Chitosan stabilized nanocrystalline iron has strong reducibility,high reaction activity and good stability.The new material will be loaded on strong adsorbable carbon.The new material will have good performance and stability.At the same time,the material has strong magnetic properties and can be applied to the recovery and adsorption of heavy metals.The study uses chitosan modified nano iron to load to the biological carbon water hyacinth,in order to preparating the chitosan modified biochar?the following is referred to as"the material"?,detecting microstructure characteristics and functional groups on the chitosan modified biochar structure by means of representation,and the the adsorption mechanism of chitosan modified biochar by static batch experiments and regeneration tests and magnetic separation test,,the main conclusions are as follows:?1?The characterization results showed that there was a flower like zero valent iron nanoparticle with particle size distribution of 37nm on the surface of the material.After modification,the C,H,O,N ratio and functional group composition of biochar changed little.Compared with the water hyacinth bio carbon,the total specific surface area increased by 62.4%,the total pore volume increased by 32.6%,and the average diameter of the pore diameter increased by 11.6%?2?The adsorption process of the material can fit the pseudo-second-order model better,which shows that the adsorption mechanism between the chitosan modified biochar with Cr⁶⁺was mainly chemical adsorption;Its isothermal adsorption fit the Langmuir model better,which indicated that chitosan modified biochar adsorption mechanism of Cr⁶⁺for the single molecular layer adsorption.?3?The maximum adsorption capacity of chitosan stabilized Fe modified bio carbon at 25 C and pH=2.0 was 68.316 mg/g,which increased by 151.43%than that of water hyacinth biochar,and was 49.38%higher than that of nano iron modified biochar,indicating that the load of chitosan stabilized nano iron increased the adsorption energy of biochar.?4?In the acidic environment,the material have better adsorption performance;higher temperature can promote the chitosan modified biological carbon;In the low salinity environment,the basic biochar adsorption properties affected.When the salinity is more than 0.1M,the adsorption of carbon to Cr⁶⁺decreases.?5?The material have good recycling performance,after 4 times of adsorption-desorption-adsorption cycle,its adsorption capacity can still retain 68.70%;Dynamic desorption curve of the material reached desorption peak at 53min,which pour into the liquid volume is about 127mL,Ct/and C0 was 0.982.Under acidic?Ph=2.0?conditions,controlling a certain amount of magnetic seed dosage?100mg/L?and magnetic field intensity?velocity 2mL/min?can help to maximize the magnetic separation effect.The above results show that the material has excellent adsorption and regeneration performance,exhibits good stability and magnetism,and can effectively separate and recover heavy metal Cr???.