Degradation of the herbicide isoproturon by a photocatalytic process

Improving activity and stabilization of urease by crosslinking to nanoaggregate forms for herbicide degradation

Bioremediation is the most effective green protocol for degradation of environmental contaminants. Present study involves carrier free urease immobilization with synthesis of its new crosslinked aggregates using two different crosslinkers, divinyl benzene (DVB) and tripropyleneglycol dimethacrylate (TPGDA) via free radical mechanism. Resulting crosslinked ureases were further converted to nanoform (CLUNAs) using solvent evaporation technique. The activity of free and the crosslinked ureases was studied as a function of operational parameters viz. temperature (20-80), pH (2-11) and substrate concentration (5-20 mM) using urea as substrate at contact time of 10 min. Storability study of the pristine urease and CLUNAs was carried out for 40 days, and the CLUNAs were reused in 10 repeat cycles to assess their reusability. Isoproturone degradation was studied under the above-cited range of pH and temperature and results were recorded after 24 h.

The effect of natural iron oxide and oxalic acid on the photocatalytic degradation of isoproturon: a kinetics and analytical study

The photocatalytic degradation of isoproturon, a persistent toxic herbicide, was investigated in the presence of natural iron oxide and oxalic acid and under UV irradiation. The influence of the relevant parameters such as the pH and the iron oxide and oxalic acid concentrations has been studied. The presence of natural iron oxide and oxalic acid in the system effectively allow the degradation of isoproturon, whereas the presence of t-butyl alcohol adversely affects the phototransformation of the target pollutant, thus indicating that an OH radical initiated the degradation mechanism. The degradation mechanism of isoproturon was investigated by means of GC-MS analysis. Oxidation of both the terminal N-(CH₃)₂ and isopropyl groups is the initial process leading to N-monodemethylated (NHCH₃), N-formyl (N(CH₃)CHO), and CHCH₃OH as the main intermediates. The substitution of the isopropyl group by an OH group is also observed as a side process.