Binary mixture sorption of basic dyes onto wheat straw

Simultaneous adsorption of Basic Blue 3 (BB 3) and Basic Red 18 (BR 18) onto wheat straw (WS) from a binary system was studied and compared with a single dye system in a batch mode. The single-component Langmuir and Freundlich isotherm models were applied to the adsorption equilibrium data for single-component and binarycomponent systems. The equilibrium adsorption for the binary system was also analyzed by using multi-component modified Langmuir and Sheindorf-Rebuhn-Sheintuch (SRS) models. Equilibrium data of BB 3 in single and binary systems fitted more adequately to the Freundlich adsorption isotherm. For BR 18, the Langmuir model was the best one for fitting the adsorption equilibrium in single and binary systems. The pseudo-first order and pseudo-second order models were employed to fit the experimental data for the adsorption kinetics of BB 3 and BR 18 on WS from singleand binary-component systems. The pseudo-second-order model provided better correlation for the adsorption process in single-and binary-component systems. Adsorption results from the binary system indicated the competitive adsorption between dyes. The maximum adsorption capacities of WS for BB 3 and BR 18 dyes in single solution system were found as 90.91 mg g -1 and 142.86 mg g -1 , respectively, while in binary mixture they decreased to 76.92 mg g -1 and 111.11 mg g -1 , respectively, as a result of their antagonistic behavior

Heterogeneous Fenton oxidation of paracetamol using iron oxide (nano)particles.

100 mg.L-1 paracetamol aqueous solutions were treated by heterogeneous Fenton oxidation at acidic pH (2.6). Three types of iron oxides – nano- and submicro-structured magnetite, nanostructuredmaghemite – were tested as catalysts for that purpose. For each system, the paracetamol conversion and mineralization yield (Total Organic Carbon removal) were evaluated, as well as the catalyst stability upon recycling. The influence of reaction parameters such as temperature, iron amount, and hydrogen peroxide dosage was also investigated. Paracetamol mineralization was improved by high temperature and low oxidant dosage due to radical scavenging effects. In best conditions (two times the stoichiometric amount of H2O2, a temperature of 60°C, a catalyst concentration of 6 g.L-1), paracetamol was fully degraded after 5 h, but total mineralization was not yet achieved: TOC removal reached about 50% when magnetite powders were used as catalysts. All iron oxides exhibited low iron leaching (<1%) and stable catalytic activity upon first recycling

Alternative low-cost adsorbent for water and wastewater decontamination derived from eggshellwaste: an overview

As the current global trend towards more stringent environmental standards, technical applicability and cost-effectiveness became key factors in the selection of adsorbents for water and wastewater treatment. Recently, various low-cost adsorbents derived from agricultural waste, industrial by-products or natural materials, have been intensively investigated. In this respect, the eggshells from egg-breaking operations constitute significant waste disposal problems for the food industry, so the development of value-added by-products from this waste is to be welcomed. The egg processing industry is very competitive, with low profit margins due to global competition and cheap imports. Additionally, the costs associated with the egg shell disposal (mainly on landfill sites) are significant, and expected to continue increasing as landfill taxes increase. The aim of the present review is to provide an overview on the development of low-cost adsorbents derived from eggshell by-products

Linear and Nonlinear Regression Methods for Equilibrium Modelling of p-Nitrophenol Biosorption by Rhizopus oryzae: Comparison of Error Analysis Criteria

The study assessed the applicability of Rhizopus oryzae dead fungi as a biosorbent medium for p-nitrophenol (p-NP) removal from aqueous phase. The extent of biosorption was measured through five equilibrium sorption isotherms represented by the Langmuir, Freundlich, Redlich-Peterson, multilayer and Fritz-Schlunder models. Linear and nonlinear regression methods were compared to determine the best-fitting equilibrium model to the experimental data. A detailed error analysis was undertaken to investigate the effect of applying seven error criteria for the determination of the single-component isotherm parameters. According to the comparison of the error functions and to the estimation of the corrected Akaike information criterion (), the Freundlich equation was ranked as the first and the Fritz-Schlunder as the second best-fitting models describing the experimental data. The present investigations proved the high efficiency (94%) of Rhizopus Oryzae as an alternative adsorbent for p-NP removal from aqueous phase and revealed the mechanism of the separation process

Wastewater treatment in an integrated laboratory system

Integrated laboratory system consisted of three stages - activated sludge reactor, biofilter and subsurface vertical flow wetland was used to treat two types of wastewaters differed in their generation and pollution. Wastewaters from a pig farm as well as from a landfill site for domestic wastes were used in the experiments. The BOD/COD ratio of the wastewaters from a pig farm and from the landfill leachate was 0.5 and 0.07, respectively. In the first stage of the integrated system was achieved COD removal (48 % for the piggery wastewater for 3 days and 62.3 % for the landfill leachate after 4 days). BOD removal (55.6 %) for the piggery wastewater was achieved in 3 days and 24.9 % - for the landfill leachate after 4 days. The decreasing of organics at aerobic conditions was accompanied with the ammonium ions decreasing - 1.5 times for the piggery wastewater and 4 times for the leachate. In the second stage - biofilter without aeration, an additional organic loading decreasing was achieved. The COD decreased from 820.9 mg/dm3 to 274.3 mg/dm3 for piggery wastewater and for the leachate - from 869.5 mg/dm3 to 423.6 mg/dm3. The BOD values decreased from 384.1 mg/dm3 to 106.8 mg/dm3 for the piggery wastewater and for leachate - from 117.8 mg/dm3 to 57.4 mg/dm3. The ammonium ions were eliminated from both types of wastewaters. In the third stage (subsurface vertical flow wetland) the emission standards for discharge into the sewage collection systems or into the water bodies are met