“…Finally, other researchers focus on the metallurgy process(Reuter, 2016) and intelligent robotics technology applied in waste management(Sarc et al, 2019). With respect to research gaps, most of the papers emphasize the need to test and validate concepts, frameworks, and models developed by the authors (Lopes de SousaJabbour et al, 2018;Chauhan, Sharma and Singh, 2019;Garrido-Hidalgo et al, 2019;Nobre and Tavares, 2020b). These findings reinforce the initial stage of knowledge in the area since many studies claimed practical applications and empirical evidence of I4.0 to CE (Lopes de SousaJabbour et al, 2018;Chauhan, Sharma and Singh, 2019;Rosa et al, 2020).…”