Application of Photo-oxidative Processes for the Remediation of Bleached Kraft Pulp Effluent

Abstract

Photo-Fenton, H2O2/UV, and H2O2/TiO2/UV processes were tested and optimized to remediate organic material from bleached pulp mill effluent. Those processes were considered as part of a tertiary treatment protocol in which the optimal pH conditions for successful installation of the processes were analyzed. In the photo-Fenton and H2O2/TiO2/UV processes, a response curve was constructed to obtain the best relative proportions for the concentrations of the reagents inside and outside the experimental space. All experimental conclusions were drawn by the analysis of the relevant COD, color, and TOC data. One of the chief findings in this work is that among the photo-oxidative paths employed, the photo-Fenton treatment furnished the highest reduction in COD (78%) and TOC (91%) via the application of a concentration ratio of H2O2 to Fe2+ of 700:3.8 (mg L−1). The H2O2/UV process demonstrated a high removal of COD (61%), color (100%), and TOC (86%) when the H2O2 concentrations were 500 mg L−1. The application of a photo-Fenton process, a heterogeneous photocatalysis coupled with hydrogen peroxide (H2O2/Fe2+/UV), can be considered as more meritorious in a materials sense relative to the H2O2/UV process because lower H2O2 amounts are used. In a broad tertiary remediation perspective, all photo-oxidative processes using high H2O2 concentrations achieved COD reductions in the range of 60−70% removal, 100% color removal, and a 70−90% reduction range for TOC.

Combining multivariate curve resolution and lumped kinetic modelling for the analysis of lignin degradation by copper-catalyzed Fenton-like systems

“…A central composite experimental design (CCD) was used. 15,16 The effects of three factors ( i.e. , [Cu( ii )], [H 2 O 2 ], and pH) were evaluated through a set of 17 experiments: 8 runs corresponding to the complete factorial design ( i.e.…”

“…13,14 The oxidation efficiency of organic pollutants in Fentonlike systems operated under dark conditions depends on several factors including temperature, pH, and concentrations of Cu(II) and H 2 O 2 . To study the effect of these variables and their interactions on lignin degradation efficiency, design of experiments (DOE) 15,16 can be used. These techniques allow selecting, on a statistical basis, a minimum number of well-chosen experiments to build response surfaces that properly describe the system behavior.…”

Modeling, simulation, and optimization of advanced oxidation technologies for treatment of polymeric wastewater

“…where k and c p are the factor number and rotatable number of center point, respectively. The critical experimental levels were chosen based on the preliminary experimental results and the values found in the open literature (Rojas et al, 2010;Silva et al, 2010;Sun and Lemely, 2011). Therefore, the data from Box-Behnken design was subjected to the quadratic model, a quadratic equation that correlates the dependent and independent variables.…”

“…The percent TOC removal rate and the "pseudo"-second order rate constant were considered as the dependent factors (process responses). The independent variables and their critical experimental levels in Table 4.13 were chosen based on preliminary experimental results and the literature values (Rojas et al, 2010;Silva et al, 2010;Sun and Lemley, 2011). The statistical softwares, STATISTICA (trial version 10.0) and Design-Expert (trial version 8.0), were used for the regression analysis and the parameter estimation of the response functions.…”

Optimisation of photo‐Fenton‐like degradation of aqueous polyacrylic acid using Box‐Behnken experimental design

“…The independent variables and their critical experimental levels as shown in Table 1 were chosen based on the preliminary experimental results and the values reported in the open literature. [34][35][36] In the RSM, as the initial step, an appropriate approximation which is generally a first-order model is applied to find the true functional relationship between the response function and the set of factors. However, in the first-order model, there is a lack of fit due to the existence of the surface curvature.…”