Display omitted •One-pot method to prepare calixarene adsorbent by electron beam irradiation.•TC4A/PAA/diatomite irradiated at 90 kGy has high efficient for Cu(II) adsorption.•The maximum adsorption capacity of TC4A/PAA/diatomite (90 kGy) for Cu(II) is 123.30 mg/g.•The microstructure and adsorption performance of TC4A/PAA/diatomite were studied. Chemical grafting of calix4arene is a common method to prepare high-performance calix4arene adsorbents for heavy metals, however, the chemical grafting process consumes much time and a large amount of heating energy due to the tedious steps. Herein, a thiacalix4arene/acrylic polymer/diatomite (TC4A/PAA/diatomite) adsorbent was fast fabricated by electron beam irradiation induced grafting, polymerization and crosslinking technique only in one-pot for the removal of Cu(II) as an important form of heavy metal pollution. Characterization by Fourier transform infrared (FTIR) spectra, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), diffuse reflectance UV–visible spectra and positron annihilation lifetime spectra (PALS) disclosed that the eco-friendly and low-cost TC4A/PAA/diatomite irradiated at 90 kGy namely TC4A/PAA/diatomite (90 kGy) with strong complexing ability owing to many functional groups such as carboxyl, hydroxyl etc in it. The effects of electron beam irradiation dose, initial solution pH, and initial concentration of Cu(II) on the adsorption performance of TC4A/PAA/diatomite were investigated. The isotherm adsorption data of Cu(II) in TC4A/PAA/diatomite (90 kGy) are more suitable for the Langmuir model with the maximum adsorption capacity of 123.30 mg/g. In addition, the bifunctional TC4A/PAA/diatomite (90 k Gy) can efficiently remove Cu(II) and display excellent reusability properties. The adsorption mechanism was further analyzed by FTIR, SEM, X-ray photoelelctron spectroscopy (XPS), diffuse reflectance UV–visible spectra and PALS. This study provides a fast, efficient and eco-friendly synthesis method of calix4arene adsorbent, conducing to the design of material innovation. Meanwhile, TC4A/PAA/diatomite (90 kGy) has potential application prospects in the treatment of practical Cu(II) contaminated wastewater.