An integrated process involving adsorption and photocatalysis are utilized for the breakdown of three different pesticides such as 2,4-D, 4-CPA and TCP. Photo-catalysts were fabricated using polythiophene supported TiO2 composites and utilized for the pesticides degradation under UV light irradiation. The synthesized materials were characterized for elemental, microscopic, spectroscopic and spectrophotometric properties. The outcome shows that polythiophene supported titanium dioxide systems can successfully facilitate the breakdown of pesticides under UV irradiation. The photocatalytic effectiveness of the TiO2 catalyst was significantly improved by the addition of polythiophene. Maximum amount of adsorption capacity for 2,4-D, 4-CPA and TCP were 8.18, 6.333, and 9.681 mg/g by pTh-1. The modified version of the Langmuir-Hinshelwood (L-H) model explained the inter-relationship between the adsorption and photodegradation. Results explained that the pTh-1 catalyzed photodegradation of 4-CPA, TCP and 2,4-D exists the surface reaction which was rate-limiting. Langmuir- Hinshelwood and electrical energy per order (EEO) model provided good fit with batch-mode experiments. Furthermore, these models were successful in elucidating the mechanisms of photocatalytic degradation when pTh-1 was available in the reaction mixture.

A detailed coastal water monitoring near Diu coast, western part of India was performed from October, 2020 to May, 2021 covering the 2nd lockdown time. Average monthly fluctuation from 7 different sampling stations of total 9 physico-chemical parameters such as pH, salinity, turbidity, nitrite (NO2), nitrate (NO3), ammonia (NH3), phosphate (PO4), total alkalinity and silicate were recorded. Initially, Mann-Kendall trend test for all the 9 parameters showed non-zero trend, which may be either linear or non-linear. During 2nd lockdown period, there was a fluctuation of value for parameters like pH, salinity, nitrate, nitrite and phosphate. Average total bacterial count and differential bacterial count also gradually decreased from March, 2021 sampling. Principal component analysis (PCA) plot covering all the physico-chemical parameters as well as the differential bacterial count showed a distinct cluster of all bacterial count with total alkalinity value. Subsequently, mathematical equation was formulated between total alkalinity value and all differential bacterial count. Upto our knowledge this is the first report where mathematical equation was formulated to obtain value of different bacterial load based on the derived total alkalinity value of the coastal water samples near Diu, India.