With the wide application of beryllium globally, industrial wastewater has rapidly increased. Previously, adsorption was effective in treating this issue. However, most adsorbents have a poor removal rate, primarily in the low adsorption capacity. To remove Be from industrial wastewater and overcome the disadvantages of low adsorption capacity and poor removal rate of existing adsorbents, typical agricultural waste lotus leaf was used to prepare Al-activated carbon (Al-AC) by the impregnation-calcination modification of Al(NO3)3. The theoretical maximum adsorption capacity of Al-AC was 32.86mg/g. Langmuir, Freundlich, and Temkin models were used to thermodynamically analyze Al-AC, and adsorption thermodynamics demonstrated that the adsorption reaction of Al-AC was endothermic. Through characterization analysis, the specific surface area of the modified AC increased from 4.3573 to 155.87 m2/g. This study provides a new approach to preparing and modifying AC and a new method for removing Be from industrial wastewater.