Oilfield wastewater has a significantly negative influence on the recovery efficiency due to its hypersalinity. Therefore, magnetic graphene oxide (GO) modified with ethylene diamine tetraacetic acid (EDTA) and grafted by polyethylene glycol (PEG) nano-adsorbent was prepared to remove the Ca²⁺ and Cr⁶⁺ in Jidong Oilfield wastewater specifically. It was noteworthy that PEG-g-EDTA/Fe₃O₄/GO nano-adsorbent had excellent adsorption performance, with removal ratios up to 71.6% for Ca²⁺ and 42.7% for Cr⁶⁺ at 30 min. After the fifth recycling run, the nano-adsorbent still remained with high removal ratios (69.3% for Ca²⁺ and 30.5% for Cr⁶⁺) and high reuse rates (89.4% for Ca²⁺ and 95.2% for Cr⁶⁺), indicating that the nano-adsorbent had outstanding adsorption-desorption efficacy and high reusability. The adsorption test results demonstrated that the total salinity of the treated oilfield wastewater decreased by about 5,000 ppm, and the displacement efficiency further increased by 12.5% by chemical flooding compared with the untreated wastewater. Therefore, PEG-g-EDTA/Fe₃O₄/GO nano-adsorbent is an adsorbent with excellent potential which can effectively remove Ca²⁺ and Cr⁶⁺ in oilfield wastewater to enhance oil recovery (EOR).

油田废水的高盐度对采收率有显着的负面影响。为此，制备了乙二胺四乙酸（EDTA）改性并接枝聚乙二醇（PEG）纳米吸附剂的磁性氧化石墨烯（GO），专门用于去除冀东油田废水中的Ca ²⁺和Cr ⁶⁺。值得注意的是，PEG- g -EDTA/Fe ₃ O ₄ /GO 纳米吸附剂具有优异的吸附性能， 30 min对Ca ²⁺和Cr ⁶⁺的去除率分别高达71.6%和42.7%。在第五次循环运行后，纳米吸附剂仍保持较高的去除率（Ca ²⁺为 69.3% ，Cr 为 30.5%）⁶⁺）和高重复利用率（Ca ²⁺为89.4% ，Cr ⁶⁺为95.2% ），表明该纳米吸附剂具有出色的吸附-解吸效率和较高的重复利用率。吸附试验结果表明，与未经处理的废水相比，处理后的油田废水总盐度降低了约5000 ppm，化学驱驱替效率进一步提高了12.5%。因此，PEG- g -EDTA/Fe ₃ O ₄ /GO纳米吸附剂是一种具有良好潜力的吸附剂，可以有效去除油田废水中的Ca ²⁺和Cr ⁶⁺，提高采收率（EOR）。