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Rapid urbanization and industrialization can lead to the accumulation of toxic halogenated organic pollutants (HOPs) in soil environments, which poses a risk to the wider eco-environment. In this study, we explored the occurrence and health risks of halogenated organic pollutants by analysing surface soil samples (n = 209) collected from various E-waste dismantling, industrialized and urban areas, rural areas and remote areas in Zhejiang Province, China. The mean average concentrations (d.w.) and range (min-max) of the HOPs were Dechlorane plus (DP) = 0.14 ng/g (below detection limit ( industrialized and urban areas > rural areas > remote areas. Nevertheless, we observed high detection ratios in rural and remote areas, indicating scattered industrialization led to ubiquitous HOP soil pollution in the region.

It is important to remove excessive concentrations of boric acid from water because it can lead to environmental problems. However, current adsorbents are limited in separating boric acid from water due to their low desorption capability and poor selectivity for boric acid. In this study, the authors developed a functional cellulosic paper via crosslinking cellulose and tannic acid with chitosan to efficiently and reversibly remove boric acid from water. The adsorption capacity reached 769 mg/m2 according to the Langmuir model. The corresponding desorption rate of the chitosan/tannic acid-modified paper exceeded 80% in the whole flow rate region ranging from 15 to 250 mL/h. The reversible adsorption and desorption of boric acid were attributed to the formation and dissociation of the borate bond between the tannic acid and boric acid, respectively, at different pH values. This study improved the selectivity, batch adsorption, expensive carriers, and desorption difficulties of existing boric acid adsorption materials. This approach offers a new way to design highly efficient adsorption/desorption materials by constructing reversible chemical bonds for removal of other pollutants.

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