The present study investigated the efficiency of catalytic wet oxidation (CWO) for the destruction of three phenolic compounds (phenol, o-cresol and 2,5-dimethylphenol) individually as well as in mixture (phenolics concentration = 10 g/L, NaOH concentration = 10 g/L, chemical oxygen demand (COD) = 24000 mg/L, total organic carbon (TOC) = $7800 mg/L and pH $13). The oxidative hydrothermal reaction was carried out in a laboratory scale high pressure batch reactor (capacity = 0.7 L) at moderate temperature (120-160 C) and pressure (oxygen partial pressure = 0.8 MPa) conditions in the presence of a heterogeneous catalyst (i.e., 5% Cu/activated carbon). After 4 h CWO reaction on the mixture of phenolics at a reaction temperature of 160 C and initial reaction pH of 9.0, TOC and COD were reduced by $90% and 82%, respectively. The phenolics removal was mainly due to the oxidation reaction and the contribution of other reactions such as adsorption and/or hydrolysis was lower. The copper leaching in the solution was found to be 15-26 ppm. The characterization of recovered catalyst showed increase in carbon content thus confirming the deposition of carbonaceous deposit.

Catalytic wet oxidation (CWO) of phenolic wastewater containing phenol, o-cresol, and 2,5-dimethylphenol was carried out in a batch reactor (phenolics = 10 g/L, chemical oxygen demand (COD) = 26 000 mg/L, and total organic carbon (TOC) = 7900 mg/L). Using the Box–Behnken experimental design (BBD) approach, the following optimum CWO conditions (catalyst: 5% Cu/AC) for phenolics degradation were found: C cat = 3.4 g/L, T = 148 °C, P O2 = 0.61 MPa, and pH = 7.4. Under these conditions, TOC and COD removals of 88 and 90%, respectively, were obtained after 4 h of reaction. p-Benzoquinone and hydroquinone were identified as major intermediates, whereas a mixture of carboxylic acids was detected in treated wastewater. At higher oxygen pressures (stoichiometric and above), mineralization of phenolics was improved although the overall degradation was lower probably due to overoxidation. Reaction kinetics, reusability of the catalysts, and detailed characterization of spent catalysts are also discussed in this paper.

Diammonium Phosphate (DAP) is an important crop nutrient for plants and its use is increasing day by day with increase in population. Life cycle assessment (LCA) is an important tool in the evaluation of the environmental performance of the product/ system throughout the life cycle. In this paper, LCA has been used to evaluate the performance of the Diammonium Phosphate (DAP) fertilizer production. The system investigated includes DAP production process. The quantification of environmental emissions, material and energy usage are quantified and environmental effects are assessed. The impact categories most affected by the DAP production, are respiratory inorganics and terrestrial acid/nitrification. Interpretations have been made and recommendations are given for operational improvements in DAP production