Pesticides and herbicides have been used extensively in agricultural practices to control pests and increase crop
yields. Paraquat (
PQT2+, 1,1-dimethyl-4,4-dipyridinium chloride) is one of the herbicide that belois classified as
bipyridines and is used over the world. The objective of this study is to use ketoenol–pyrazole receptor functionalized
silica hybrid as adsorbent for removal PQT2+
from aqueous solution. The adsorbent was synthesized, and
characterized using scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), Thermal analysis and
other techniques. Different experimental parameters such as the effect of the amount of adsorbent, solution pH and
temperatures and contact times were studied. Pseudo-order kinetics models were studied, and our data followed a
pseudo second order. Experimental data were analyzed for both Langmuir and Freundlich models and the data fitted
well with the Langmuir isotherm model. To understand the mechanism of adsorption, thermodynamic parameters
like standard enthalpy, standard Gibbs free energy, and standard entropy were studied. The study indicated that the
process is spontaneous, exothermic in nature and follow physisorption mechanisms. The novelty of this study showed
surface of pyrazol-enol-imine-substituted silica (SiNPz) has the ability to highlight the surface designed for efficient
removal of PQT2+,
from aqueous solutions more than other studies. The study also showed that ketoenol–pyrazole
receptor can be regenerated in five cycles using HNO3
without affecting its adsorption capacity.
Keywords: Ketoenol–pyrazole receptor, Adsorption, Paraquat, Kinetics, Isotherm

Title

BMC Chemistry

Publisher

Springer Nature

Publisher Country

Switzerland

Indexing

Scopus

Impact Factor

None

Publication Type

Both (Printed and Online)

Volume

86

Year

2019

Pages

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