Removal and degradation of triazole fungicides using Ag/PEG-CuO: an efficient adsorbent-catalyst coupling process

Resonant nonlinear optical absorption of silver nanoparticles was studied experimentally via open aperture Z-scan using 130 fs, 400 nm laser pulses. Experimental results show that, at low laser intensity, silver nanoparticles can exhibit saturated absorption. While at high laser intensity, it shows reverse saturated absorption. The saturable absorption is explained in terms of ground state plasmon bleaching, while the reverse saturable absorption is believed to be from two-photon absorption. Saturable optical intensity and two-photon absorption coefficient were obtained to be 1.3×1010 W/m2 and 3.3×10−10 m/W, respectively. The energy relaxation process of Ag nanoparticles after laser excitation was studied via pump-probe technique at 400 nm. Experimental results demonstrated that energy relaxation included electron-phonon coupling process with time constant τ1=(713±50) fs, and phonon-phonon coupling process with time constant τ2=(25.2±3) ps, respectively.

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Synthesis and characterization of Cu(OH)2-NWs-PVA-AC Nano-composite and its use as an efficient adsorbent for removal of methylene blue

Scientific Reports ◽

10.1038/s41598-021-84797-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sivarama Krishna Lakkaboyana ◽

Khantong Soontarapa ◽

Nabel Kalel Asmel ◽

Vinay Kumar ◽

Ravi Kumar Marella ◽

...

Keyword(s):

Methylene Blue ◽

Kinetic Models ◽

Batch Reactor ◽

Maximum Adsorption Capacity ◽

Nano Composite ◽

Adsorption Processes ◽

Intra Particle Diffusion ◽

Short Time ◽

Efficient Adsorbent

AbstractThe present study focused on the synthesis of copper hydroxide nanowires decorated on activated carbon (Cu(OH)2-NWs-PVA-AC). The obtained Cu(OH)2-NWs-PVA-AC Nano-composite was distinguished by XRD, SEM, EDX, BET, FTIR and XPS respectively. Besides, different variables such as solution pH, and initial dye concentration, contact time, and temperature were performed on the adsorption efficiency of MB in a small batch reactor. Further, the experimental results are analyzed by various kinetic models via PFO, PSO, intra-particle diffusion and Elovich models, and the results revealed that among the kinetic models, PSO shows more suitability. In addition, different adsorption isotherms were applied to the obtained experimental data and found that Langmuir–Freundlich and Langmuir isotherm were best fits with the maximum adsorption capacity of 139.9 and 107.6 mg/g, respectively. The Nano-composite has outstanding MB removal efficiency of 94–98.5% with a span of 10 min. and decent adsorption of about 98.5% at a pH of 10. Thermodynamic constants like Gibbs free energy, entropy, and enthalpy were analyzed from the temperature reliance. The results reveal the adsorption processes are spontaneous and exothermic in nature. The high negative value of ΔG° (− 44.11 to − 48.86 kJ/mol) and a low negative value of ΔH° (− 28.96 kJ/mol) show the feasibility and exothermic nature of the adsorption process. The synthesized dye was found to be an efficient adsorbent for the potential removal of cationic dye (methylene blue) from wastewater within a short time.

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