The development of low-cost and highly effi cient adsorbents is essentially needed for removing Hg 2+ species from desulfurization

sludge leaching wastewater. In this study, a series of novel Cu-modifi ed attapulgite (Cu–ATP) adsorbents were

synthesized via a simple HNO 3 treatment combined with an improved impregnation method. The Hg 2+ removal effi ciency

of these Cu–ATP adsorbents was investigated in simulated leaching wastewater. The eff ects of HNO 3 concentration, Cu

precursor, Cu-loading content, and other adsorption conditions on Hg 2+ removal using Cu–ATP were investigated. The

results demonstrated that Cu–ATP prepared with CuSO 4 as the precursor and treated with 3 mol/L HNO 3 showed excellent

Hg 2+ removal performance. Moreover, with increasing adsorbent content and adsorption time, the Hg 2+ removal effi ciency

of Cu–ATP fi rst increased and then stabilized. However, with an increase in pH value, the Hg 2+ removal effi ciency fi rst

increased and then decreased, whereas the removal showed a decreasing trend with increasing initial Hg 2+ concentration.

The adsorption kinetics results indicated that Hg 2+ adsorption on Cu–ATP was well described by the pseudo-second-order

model. Furthermore, various characterization methods, including Brunauer − Emmett − Teller analysis (BET), X-ray diff raction

(XRD), and X-ray photoelectron spectroscopy (XPS), were employed to analyze the physicochemical properties of the

adsorbents. The analyses confi rmed that the superior Hg 2+ removal effi ciency of Cu–ATP was mainly due to the complexation

of Hg 2+ with chemisorbed oxygen produced by Cu doping and S species generated from the Cu precursor (CuSO 4 ). These

fi ndings underscore the potential of Cu–ATP as a cost-eff ective adsorbent for removing Hg 2+ from wastewater.