Studies on the Removal of Malachite Green from Its Aqueous Solution Using Water-Insoluble ß-Cyclodextrin Polymers.

The rising global pollution of natural waters by dyes has brought to light the need for adaptable and efficient removal techniques. To create water-insoluble ß-cyclodextrin (ß-CD) polymers like CA/-CD, TA/-CD, and MA/-CD, several organic acids including citric acid (CA), tartaric acid (TA), and malic acid (MA) were cross-linked with ß-cyclodextrin in this study. The obtained polymers were characterized by different advanced analytical techniques such as FTIR, SEM, and UV-vis spectrophotometry. Malachite green dye was removed from aqueous solutions using the synthesized polymers by adsorption. The adsorption investigation was conducted under several conditions, including pH, adsorbent mass, dye concentration, temperature, contact time, adsorption isotherm, and kinetics. The adsorbent CA/ß-CD shows the highest adsorption of MG dye in all of the conditions because it contains a high number of carboxyl groups. The negatively charged carboxyl ions of CA/ß-CD attract the positively charged MG dye electrostatically and remove MG from aqueous media with an efficiency of 91%. As a result, the findings indicated that water-insoluble polymers based on ß-cyclodextrin are well-suited as inexpensive adsorbents to remove colors from aqueous media.

GO/CuO Nanohybrid-Based Carbon Dioxide Gas Sensors with an Arduino Detection Unit.

A gas sensor is a device that detects the presence of gases in a specific area. This research work demonstrates the effectiveness of gas sensors based on graphene oxide (GO) and copper oxide (CuO) semiconductor nanomaterials for the detection of carbon dioxide. GO and CuO were prepared by the modified Hummer's method and precipitation method using CuCl2 as a precursor, respectively. These materials are made into a hybrid using poly(vinyl alcohol) (PVA)/poly(vinylpyrrolidone) (PVP) polymer solutions of low concentrations and are spin coated onto the pattern-etched copper-clad substrate. The sensor is tested using a source measurement unit (SMU) to obtain the change in the resistance of the sensor in open air and in a carbon dioxide environment. The fabricated sensor with an Arduino microcontroller detection unit showed a good sensing response of 60%.