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Diclofenac in wastewater poses a significant threat to both human health and ecological systems. In this work, two three-dimensional (3D) hierarchical porous polymer/carbon material, namely activated carbon (AC) and graphene oxide (GO) composites were fabricated using a vat polymerization-based 3D printing method. Firstly, in order to produce high-performance amino-functionalized graphene/activated carbon polymer composites, their functionalization by diethylenetriamine (DETA) was performed. A porogen solvent was employed in order to induce porosity in the polymer matrix (base resin, BR) via phase separation during the photopolymerization process and led to the creation of two types of composites: BR-AC-DETA and BR-GO-DETA. The physicochemical characteristics of the composites were comprehensively analyzed across the nano to macroscale range. The adsorbent materials were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, Fourier Transform Infrared spectroscopy (FTIR), contact goniometry and mechanical compression testing. The resulting 3D adsorbents demonstrated porosity at various length scales due to their porous lattice structure, porous polymer matrix and inherent porosities of the carbon materials, as confirmed by nitrogen porosimetry. In the second stage, batch adsorption experiments were conducted using the 3D-printed amino-functionalized adsorbents to evaluate the effects of the pH, contact time and initial diclofenac concentration on the adsorption performance. The results revealed that the 3D printed BR-GO-DETA composite exhibited excellent water contaminant removal performance for diclofenac. A maximum adsorption capacity of 91.5 mg/g at pH 7 at 30 °C was achieved according to Langmuir model, while kinetic parameter analyses elucidated the adsorption process. In addition, the regeneration performance of the adsorbent was examined. The 3D printed BR-GO-DETA composite showed excellent regeneration potential, exhibiting reusability for up to five adsorption–desorption cycles. Post-printing modification by DETA enhanced diclofenac removal efficiency by sevenfold and transformed the material's surface from hydrophobic to hydrophilic. We also evaluated the economic feasibility of the 3D printed BR-GO-DETA composite. Based upon experimental models, we determined the cost price the composite and compared the three main phases of the synthesis process. The cost price of 3D printed BR-GO-DETA composite is estimated as 2.28 €/adsorbent. Moreover, the raw materials contribute the overwhelming majority of this cost and the intensified process of posttreatment is the most expensive among the other processes.
Efthymiopoulos et al. (Wed,) studied this question.