赤泥/废菌渣磁性生物炭的制备及对水中诺氟沙星的吸附

Preparation of red mud/waste bacterial residue magnetic biochar and removal of norfloxacin in water

以氧化铝行业废弃物赤泥和食用菌产业废弃物菌棒为原料,采用共热解法制备赤泥/废菌渣磁性生物炭(RMMBC),解析其形貌特征、孔隙结构及表面官能团变化等情况,探究其对水中诺氟沙星(NOR)的吸附效果,通过吸附动力学和等温吸附特性探究其吸附机制,并在实际废水进行试验。结果表明,最佳制备条件为原料比(赤泥、废菌渣、尿素)1∶2.5∶0.5、煅烧时间1 h、煅烧温度700℃。水中NOR浓度为10 mg/L,投加0.25 g RMMBC,其对NOR的最大去除率为96.3%。结果表明,RMMBC具有较大的比表面积(59.295 m^(2)/g)、孔体积(20.157 cm^(3)/g)和饱和磁化率(16.735 emu/g)。RMMBC准二级动力学和Freundlich等温模型能较准确地描述NOR在RMMBC上的吸附过程,表明化学吸附可能是NOR在RMMBC上吸附的主要机制,主要为π-π相互作用、表面络合、疏水作用、氢键和静电作用。利用赤泥和废菌渣制备磁性生物炭吸附效果显著,兼具便于从水体中分离的优势,避免对环境造成二次污染,不仅为低成本处理抗生素废水提供新思路,还有助于实现赤泥与废菌渣的稳定化、无害化、资源化利用,实现“以废治废”的环保目标。

Using red mud from alumina industry waste and edible fungus industry waste fungus rod as raw materials,red mud/waste fungus magnetic biochar(RMMBC)was prepared by co-pyrolysis method,and its morphological characteristics,pore structure and surface functional group changes were analyzed,its adsorption effect on norfloxacin(NOR)in water was explored,and its adsorption mechanism was explored by adsorption kinetics and isothermal adsorption characteristics,and tested in actual wastewater.The results showed that the optimal preparation conditions were raw material ratio(red mud,waste bacterial residue,urea)1∶2.5∶0.5,calcination time 1 h,calcination temperature 700℃.The maximum removal rate of NOR was 96.3%when a NOR concentration was 10 mg/L and 0.25 g RMMBC was added.The results showed that RMMBC had a large specific surface area(59.295 m^(2)/g),pore volume(20.157 cm^(3)/g)and saturation magnetic susceptibility(16.735 emu/g).The quasi-secondary kinetics of RMMBC and the Freundlich isothermal model can accurately describe the adsorption process of NOR on RMMBC,indicating that chemisorption may be the main mechanism of NOR adsorption on RMMBC,mainly includingπ-πinteraction,surface complexation,hydrophobicity,hydrogen bonding and electrostatic interaction.The use of red mud and waste bacterial residue to prepare magnetic biochar adsorption effect is remarkable,which has the advantage of easy separation from the water body to avoid secondary pollution to the environment,which not only provides new ideas for low-cost treatment of antibiotic wastewater,but also helps to realize the stability,harmlessness and resource utilization of red mud and waste bacterial residue,and achieves the environmental protection goal of“waste treatment”.