Gold nanoparticles (AuNPs) were synthesized by the green method with activated Cochlospermum gossypium (carboxymethylated Cochlospermum gossypium gum or carboxymethylated gum kondagogu: CMGK) as stabilizer and reducing agent. The obtained size of AuNPs was 11 ± 2 nm. The impacts of HAuCl₄ concentration, CMGK concentration, and reaction time on the synthesis of AuNPs were investigated. The techniques, UV − visible spectroscopy, FTIR, DLS, TEM, and powder XRD, were used for characterization. The reducing capacity of the synthesized CMGK-AuNPs was tested for reduction of 4-nitrophenol (4-NP) along with NaBH₄. The effects of NaBH₄, catalyst dose, and temperature were studied for reduction of 4-NP. The AuNPs showed good antibacterial activity against E. coli and Bacillus subtilis. The outcomes of the study indicated that CMGK–AuNPs have notable antimicrobial and environmental applications.

In this study, novel adsorbents were developed by functionalizing multiwalled carbon nanotubes with frankincense (Fr-fMWCNT) and adding iron oxide (Fe₃O₄) to the adsorbent (Fr-fMWCNT-Fe₃O₄). The morphology, surface characteristics, and chemical nature of the synthesized samples were analyzed by using various characterization techniques. The prepared adsorbents were then applied for the elimination of the toxic dye, crystal violet (CV), from water-based solutions by employing a batch adsorption method. The effectiveness of materials for the adsorption of CV was investigated by tuning various effective experimental parameters (adsorbent dosage, dye quantity, pH, and contact time). In order to derive adsorption isotherms, the Langmuir and Freundlich adsorption models were investigated and compared. The Fr-fMWCNT and Fr-fMWCNT-Fe₃O₄ were found to remove 85 and 95% of the CV dye within 30 min of the adsorption experiment at pH 6, respectively. It was found that a pseudo-second-order reaction rate was consistent with the experimental adsorption kinetics. The equilibrium data demonstrated that the Langmuir model adequately explained the adsorption behavior of the CV dye on the Fr-fMWCNT and Fr-fMWCNT-Fe₃O₄ surfaces, respectively. According to the Langmuir study, the highest adsorption capacities of the dye are 434 mg/g for Fr-fMWCNT and 500 mg/g for Fr-fMWCNT-Fe₃O₄. Remediation of the CV dye using our novel composite materials has not been reported previously in the literature. The synthesized Fr-fMWCNT and Fr-fMWCNT-Fe₃O₄ adsorbents can be economical and green materials for the adsorptive elimination of CV dye from wastewater.

Aquatic pollution, which includes organic debris and heavy metals, is a severe issue for living things. Copper pollution is hazardous to people, and there is a need to develop effective methods for eliminating it from the environment. To address this issue, a novel adsorbent composed of frankincense-modified multi-walled carbon nanotubes (Fr-MMWCNTs) and Fe₃O₄ [Fr-MWCNT-Fe₃O₄] was created and subjected to characterization. Batch adsorption tests showed that Fr-MWCNT-Fe₃O₄ had a maximum adsorption capacity of 250 mg/g at 308 K and could efficiently remove Cu²⁺ ions over a pH range of 6 to 8. The adsorption process followed the pseudo-second-order and Langmuir models, and its thermodynamics were identified as endothermic. Functional groups on the surface of modified MWCNTs improved their adsorption capacity, and a rise in temperature increased the adsorption efficiency. These results highlight the Fr-MWCNT-Fe₃O₄ composites’ potential as an efficient adsorbent for removing Cu²⁺ ions from untreated natural water sources.