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A technique for green manufacturing of zinc oxide based nanoparticles utilising cassava peel has been approached in this research for antibacterial investigation. Especially, the cassava peel is an agro waste from starch and food processing industries and the extract of Cassava peel is used for synthesising the zinc oxide nanoparticles (ZnO-NPs). The peel based zinc oxide nanoparticles were synthesized using bioreduction method. The plasmon peak from UV–Visible spectroscopy is observed at 380 nm, while the XRD shows an average crystallite size of 67.31nm with hexagonal structure and also the stability of bio synthesised nanoparticles are confirmed by FTIR study. Additionally, FESEM confirms the structure is found to be spherical whereas Zeta potential analysis has confirmed the nanoparticles have a stable and well-dispersed form. Furthermore, the anti bacterial study against bio synthesized ZnO-NPs is carried out for both gram positive and gram negative bacteria. Therefore, the results proved that the bacteria are found to be more active against the synthesized nanoparticles.

In this study, an attempt is made to understand the effectiveness on initial treatment of coconut shell on the strength of concrete. The coconut shell materials obtained from the agricultural wastes are used as a replacement for coarse aggregate in conventional concrete. From the particle size distribution graph, the CS aggregates follow a similar trend of smooth grain distribution when compared to conventional aggregates. Coconut shell aggregates were treated using different method with the solutions of sodium silicate, calcium hydroxide, polyvinyl alcohol and with heat. Treated coconut shells were tested for water absorption and their resistance to crushing and impact. Water absorption of PVA treated aggregates was reduced from 17.7% to 4.0% portraying the effectiveness of pre-treatment procedure. Compared to the untreated coconut shell aggregates, the impact and crushing values of heat treated ones reduced by 75.8% and 87.8% respectively. Coconut shell concrete specimens were tested for 28-day compressive strength, split tensile strength and flexural strength. The results of treated coconut shell concrete were compared with untreated coconut shell concrete. Compressive and split tensile strengths of CS concrete also increased with heat treatment whereas the flexural strength improved due to the calcium hydroxide treated aggregates. Micro-structural characterisation using Scanning Electron Microscope (SEM) analysis showed the presence of strong interface between the aggregate particles and concrete.

This work focuses on the use of carbon-coated magnetic cobalt ferrite nanoparticles as catalysts for catalytic wet peroxide oxidation (CWPO) of the emerging concern pollutant paracetamol (PCM). The magnetic core of the catalyst is composed of CoFe2O4 developed by a sol-gel method. The core is subsequently coated with a formaldehyde-resorcinol resin and TEOS, further carbonized at 600 ºC, and etched with NaOH to create a yolk-shell structure denoted as CoFe2O4@void@C. X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transformed infra-red (FTIR) analysis revealed that the uncoated core is composed of a CoFe2O4 cubic spinel structure with a crystallite size of 53 nm calculated using the Williamson-Hall (W-H) method, matching very well the average size observed by TEM (53.51  4.2 nm). Comparing the performances of CoFe2O4@void@C and the bare CoFe2O4 in the CWPO of paracetamol, total organic carbon (TOC) removals of 58% and 46% are obtained respectively after 24 h of reaction. An empirical kinetic model based on second-order and autocatalytic expressions was developed to suitably describe the decomposition of H2O2 and the removal of paracetamol using CoFe2O4@void@C as catalyst. The disappearance of TOC was well-described (r2 = 0.98) by a lumped kinetic model as the sum of TOCA, TOCB and TOCC, where TOCA is the TOC of the PCM, TOCB refers the intermediate products and TOCC is the TOC of the final products obtained during the CWPO of PCM.

The Membrane Bio-Reactor (MBR) technology offers a series of environmentally-friendly advantages, such as high quality effluent, pathogens removal capacity and avoided use of chemicals for disinfection, allowing it to be regarded as an environmentally friendly technology, when applied for wastewater treatment. However, membrane fouling still remains a major drawback, preventing its widespread application for municipal or industrial wastewater treatment. The use of additives (i.e. adsorbents, bio-carriers etc.) is considered to be among the major strategies implemented for membrane fouling control over the last few years. The present work examines the influence of bio-carriers addition, as well as of zeolite powder on the reversible and irreversible membrane fouling of a lab-scale MBR. High-strength synthetic municipal wastewater (with BOD5 around 1000 mg/L) was fed as the substrate for the activated sludge process and a flat-sheet microfiltration membrane was operated for solids (biomass) - liquid separation at the flux of 17 L/m2h. The obtained results showed that the addition of zeolite contributed mainly to the alleviation of irreversible fouling, leaving the reversible fouling practically unaffected, while the addition of bio-carriers had quite the opposite effect. In addition, it was shown that the lab-scale MBR system operated successfully, treating a high-strength synthetic municipal wastewater, as high removals were observed in terms of both organics and especially of ammonium removal (over 98%).