Lopez presented three researches at ICMEN 2023

Engr. Edgar Clyde R. Lopez, Ph.D. Chemical Engineering candidate, presented three researches at the 7th International Conference on Materials Engineering and Nanotechnology (ICMEN 2023), November 4-5, 2023, via Zoom.

Adsorptive Removal of Methyl Orange in Water using PAN/PVP/CD-MOF Composite Beads

Cyclodextrin metal-organic frameworks (CD-MOFs) exhibit permanent porosity, which makes them an ideal adsorbent material. However, the instability of CD-MOFs in water limits their applications. To overcome this limitation, Lopez encapsulated CD-MOFs in polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) polymeric support to produce PAN/PVP/CD-MOF composite beads. Batch adsorption studies were performed to remove methyl orange in water. The results showed that low CD-MOF and intermediate PAN and PVP loadings led to the highest dye sorption capacities. The optimized bead formulation of PAN = 4.10 wt.%, PVP = 3.07 wt.%, and CD-MOF = 2.00 wt.%, resulted in a sorption capacity of 6.56 ± 0.59 mg/g. Overall, this study demonstrated that PAN/PVP/CD-MOF composite beads could be an excellent adsorbent for textile dye removal in water.

I’m the Problem, It’s Me: CO2 Capture by Cyclodextrin MOFs is Hindered by their Hydrophilicity

The rising levels of carbon dioxide (CO2) in the atmosphere pose a significant environmental concern due to their contribution to global warming and climate change. Post-combustion carbon capture (PCCC) and storage is one method to minimize CO2 emissions. Cyclodextrin-based metal-organic frameworks (CD-MOFs) are potential adsorbents for PCCC because of their high CO2 sorption capacity. Here, Lopez used Grand Canonical Monte Carlo (GCMC) simulations to investigate the adsorption of CO2 on various CD-MOFs. Results showed that CD-MOFs are selective for water and CO2 molecules over nitrogen and oxygen molecules. The Rb-CD-MOF had the highest CO2 uptake, while K-CD-MOF exhibited the highest isosteric heat of adsorption. However, all CD-MOFs had much higher water sorption capacity than CO2, and Cs-CD-MOF had the highest water uptake. Moreover, the results showed that CD-MOFs had lower CO2 adsorption capacity when combined with other gases than under pure gas conditions. We also discovered that hypothetical transition metal–based CD-MOFs behave similarly to alkaline metal–based CD-MOFs during combined gas sorption studies, suggesting that enhancing the ligand-coordination bond may have only a minimal effect in the hydrophobicity of the CD-MOFs. Other strategies for endowing hydrophobicity to CD-MOFs must be sought if it were to be deployed as an adsorbent for post-combustion carbon capture. Overall, this study underscores the importance of considering other gases in the performance assessment of MOFs for CO2 capture.

Evaluation of Corn Husk Powder (CHP) as a Lost-Circulation Material in Water-based Drilling Mud

Lost circulation during oil well drilling is a critical challenge, resulting in significant financial losses and environmental concerns. This study explores the utilization of corn husks as an eco-friendly alternative to traditional chemical additives in drilling fluids. Corn husks were converted into a lost-circulation material (LCM) in the form of corn husk powder (CHP). Various tests were conducted to assess the impact of CHP on the physical and rheological properties, filtration behavior, and lost circulation performance of a water-based mud system. The effect of different CHP concentrations on these properties was evaluated. The results revealed that CHP can act as a rheological modifier, enhancing the apparent viscosity, plastic viscosity, gel strength, and yield point of the drilling mud in a nearly proportional manner with increasing CHP loading. This modification can optimize the mud's ability to suspend cuttings and transport them to the surface. CHP also contributed to controlling fluid loss by forming a filter cake on the borehole wall, effectively preventing the loss of drilling mud into the formation. Additionally, CHP exhibited promise in influencing mud cake thickness and controlling lost circulation, making it a reliable LCM for water-based drilling muds. Optimization showed that a 2.10 wt. % CHP loading resulted in a drilling mud that met the API RP 13B-1 standard for rheological and fluid loss properties. This demonstrates the potential of CHP as an eco-friendly and effective additive for improving drilling mud performance, enhancing drilling efficiency, and mitigating environmental concerns. Overall, this study underscores the significance of CHP as a promising and environmentally responsible solution in the oil well drilling industry.