Pilot process of arsenic-containing groundwater purification by iron-based granular adsorbent fixed bed column
Arsenic(As)pollution in groundwater has become an important environmental issue in China.In order to purify the arsenic-contaminated groundwater in rural areas,an iron-based granular adsorbent(FMGA)capable of synchronously removing As(Ⅲ)and As(Ⅴ)from water was developed and packed into an adsorption fixed bed.A pilot-scale water treatment system was designed and established with a fixed bed as the core unit,which had a good capability for the treatment of As-contaminated groundwater.The results showed that during the continuous operation of 33 days,the residual As concentration in the effluent of the pilot-scale system was continuously below the limit of Standards for Drinking Water Quality(GB 5749-2022)(10 μg/L).The breakthrough time of the fixed bed reached 786 h in the first cycle.After the in-situ regeneration using 0.2 mol/L NaOH solution,the breakthrough time of the fixed bed for reuse could still reach 750 h,and the recovery rate of its arsenic adsorption capacity was close to 91%.The turbidity of the effluent for the pilot-scale system was close to zero,and the concentrations of iron and manganese ions were both lower than the limits of the sanitary standard(Fe<0.3 mg/L,Mn<0.1 mg/L).FMGA could be efficiently regenerated and reused without secondary pollution.The adsorption kinetics indicated that the adsorption process of As by FMGA was consistent with the quasi-second-order kinetic model,and As could be removed by chemisorption.The adsorption isotherm showed that the theoretical maximum adsorption capacity of FMGA for As was 74.94 mg/g(pH=7.0).According to the surface characterization results,the maximum load of FMGA was 89.39 N,indicating an excellent mechanical strength.
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维普
