Biomass‐derived porous material synthesized by one‐step calcination method for the magnetic solid‐phase extraction of polychlorinated biphenyls in water

Recent findings unfold that biomass materials with the micro/mesoporous structure were often treated as adsorbents for organic substances. In this work, a one‐step calcination method was adopted in the preparation of magnetic porous green bean biomass material. It has the properties of magnetism and porosity after the addition of Co(NO3)2 and high‐temperature calcination. A variety of characterizations have been operated, including energy dispersive X‐ray detector, vibrating sample magnetometer, Fourier transform infrared spectroscopy, Brunauer‐Emmett‐Teller analysis, and so on. It has a specific surface area of 168.1611 m2/g and a pore volume of 0.1764 cm3/g. The material was used in magnetic solid‐phase extraction of three polychlorinated biphenyls: 2‐chlorobiphenyl, 4‐chlorobiphenyl, and 2,2,5‐trichlorobiphenyl. Several factors were investigated, such as material amount, eluents, adsorption time, solution pH, salinity, and reusability. Under optimized conditions, good recoveries (90.24–93.34%) were achieved with the relative standard deviation in a range from 2.30 to 4.83%. Three real water samples (tap, river, and lake water) were tested to verify the accuracy of the method. This method can be successfully used in the analysis of some polychlorinated biphenyls congeners in water.