Jodeh Shehdeh, Hanbali Ghadir, Tighadouini Said, Radi Smaail, Hamed Othman, Jodeh Diana
1Department of Chemistry, An-Najah National University, P. O. Box 7, Nablus, Palestine.
LCAE, Department of Chemistry, Faculty of Sciences, Mohamed Premier University, 60000 Oujda, Morocco.
BMC Chem. 2019 Jul 9;13(1):86. doi: 10.1186/s13065-019-0599-2. eCollection 2019 Dec.
Pesticides and herbicides have been used extensively in agricultural practices to control pests and increase crop yields. Paraquat (PQT, 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 PQT 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 PQT, from aqueous solutions more than other studies. The study also showed that ketoenol-pyrazole receptor can be regenerated in five cycles using HNO without affecting its adsorption capacity.
农药和除草剂已在农业生产中广泛使用，以控制害虫并提高作物产量。百草枯（PQT，1,1-二甲基-4,4-联吡啶鎓盐）是被贝洛伊斯归类为联吡啶类的除草剂之一，在全球范围内被使用。本研究的目的是使用酮醇-吡唑受体功能化的二氧化硅杂化物作为吸附剂，从水溶液中去除百草枯。合成了吸附剂，并使用扫描电子显微镜（SEM）、核磁共振（NMR）、热分析和其他技术对其进行了表征。研究了不同的实验参数，如吸附剂用量、溶液pH值、温度和接触时间的影响。研究了伪一级动力学模型，我们的数据符合伪二级模型。对实验数据进行了Langmuir和Freundlich模型分析，数据与Langmuir等温线模型拟合良好。为了理解吸附机理，研究了标准焓、标准吉布斯自由能和标准熵等热力学参数。研究表明，该过程是自发的，本质上是放热的，遵循物理吸附机制。本研究的新颖之处在于，与其他研究相比，吡唑-烯醇-亚胺取代的二氧化硅（SiNPz）表面能够突出显示为从水溶液中高效去除百草枯而设计的表面。研究还表明，酮醇-吡唑受体可以使用硝酸再生五个循环，而不影响其吸附能力。
