Comparative assessment of pesticide adsorption capacity and antioxidant activity of Silver Dodecatungstophosphate/HΒEA Zeolite composites

Author(s):  
D. Janićijević ◽  
A. Jevremović ◽  
A. Janošević Ležaić ◽  
B. Nedić Vasiljević ◽  
S. Uskoković-Marković ◽  
...  
2018 ◽  
Vol 81 (1) ◽  
Author(s):  
Haslaniza Hashim ◽  
Wan Yaacob Wan Ahmad ◽  
Saiful Irwan Zubairi ◽  
Mohamad Yusof Maskat

Adsorption of model solution containing organic acids (octanoic and hexanoic acid) and phenolic compounds (rutin, scopoletin and quercetin) on a weak base anion exchange Amberlite IRA 67 resin was studied in a model system. This research was carried out to understand the effect of pH on single and multicompounds studied for its further use in actual system (fruit system). It was shown that the pH dependence of adsorption capacity of weak base anion exchange Amberlite IRA 67 resin had similar increasing trend on organic acids (hexanoic and octanoic acid) and phenolic compounds (rutin, scopoletin and quercetin) studied as pH values increased. In single solution of each phenolic compound, it was observed that total phenolic content (TPC) and antioxidant activity (FRAP and DPPH) gave highest values closer to neutral pH regime. The pH dependence of adsorption capacity in multicompounds solution also showed similar trend for organic acid compounds. Similar trend was also found in multicompounds solution of phenolic compounds in total phenolic content (TPC) and antioxidant activity (FRAP and DPPH). The findings obtained in this study will help to gain better understanding of the complex mechanisms of ion exchange resin and adsorption process involving multicompounds system.


Author(s):  
Uwamungu ◽  
Nartey ◽  
Uwimpaye ◽  
Dong ◽  
Hu

The evaluation of biochar application on the adsorption behavior of topramezone on soil under no-tillage (NT) and rotary tillage treatments (RT) has been assessed. Fourier Transform Infra-Red Spectrometry (FTIR), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller) (BET) were used for the biochar characterization. Batch experiments were carried out in a laboratory to assess the adsorption of topramezone on soil through equilibrium and kinetic modeling under biochar addition. The clay content has been found to be higher under NT (18.24 ± 0.01) than under RT (15.91 ± 0.02). The total organic carbon was higher under NT. The topramezone adsorption equilibrium reached after 8 and 12 h, for NT and RT, respectively. The kinetic and thermodynamic analyses showed the adsorption under both treatments matched with pseudo-second-order kinetic and Langmuir models, respectively. After biochar addition, the pesticide adsorption capacity (40 < 25 < 15 °C) increased with decreasing temperature suggesting an exothermic adsorption process while negative values of Gibbs free energy (ΔG); −1848.07 and −366.531 J mol−1; for the soil under NT and RT at 25 °C, respectively, indicated spontaneous adsorption. Negative entropy values (ΔS); −21.92 and −78.296 J mol−1K−1, for NT and RT, respectively, explained a decreased randomness process. The enthalpy was higher (p < 0.05) under RT (−23,274.6 J mol−1) than under NT (−1313.73 J mol−1). Conclusively, it was shown that the topramezone adsorption capacity was higher under NT, and biochar addition increased more pesticide adsorption under NT than under RT.


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