بهبود كيفيت آب آلوده به سرب، جيوه، نيترات و TDS با استفاده از خاكستر استخوان اصلاح شده توسط نانو ذرات آهن صفر ظرفيتي

چكيده انگليسي :

Abstract Fresh water scarcity especially in arid and semi arid regions imposed humans to use poor quality water such as industrial wastewaters domestic wastewaters agricultural land drainage and urban storm runoff The aim of this research was to use different forms of a bio waste ostrich bone to improve the quality of unconventional waters industrial effluent nitrate polluted water and saline water In this research at first the removal capacities of lead and mercury by ostrich bone adsorbents prepared in various appropriate types have been studied in a single component system using agitated batch sorption Ostrich bones were were milled and passed through a 35 mesh sieve mesh diameter 0 5 mm They were kept in a desiccator and named OBP adsorbent The dried bones were kept in a furnace for 24 h in air at 550 C and then were kept in an electrical furnace for 5 h at 800 C in a limited supply of oxygen These adsorbents were named OBA and OBC respectively All of the adsorbent were washed with deionizs water until the pH of the drain water was 7 0 2 The results showed that the main component of ostrich bone adsorbents is calcium hydroxyapatite with Ca P ratio is 1 49 1 58 and 1 59 for OBP OBA and OBC respectively The order of adsorption found for Pb II and Hg II ions on the adsorbents was OBC OBA OBP Then OBA supported nanoscale zero valent iron OBA nZVI was synthesized by the sodium borohydride reduction method characterized with electron microscopy SEM energy dispersive x ray spectroscopy SEM EDX fourier transform infrared FT IR x ray diffractometer XRD speci c surface area BET and point of zero charge pHPZC The OBA nZVI adsorbent was used for the removal of Pb II and Hg II ions nitrate and total dissolve solids from un conventional water The in uence of different sorption parameters such as contact time initial concentration of metal ions the dosage of OBA nZVI pH value of the solutions competitive adsorption behavior and ionic strength were investigated on the removal of Pb II and Hg II Kinetic data are well tted by a pseudo second order model and the equilibrium data were analyzed by Langmuir Freundlich model very well with high correlation coef cient The maximum adsorption capacities of OBA nZVI adsorbent towards Pb II and Hg II are 138 6 and 145 1 mg g 1 respectively Thermodynamic parameters i e G 0 H 0 S 0 and Ea have also been calculated for the system and the sorption process was found to be endothermic This study demonstrated that OBA nZVI which characterized by high specific surface area and reactivities could quickly reduce nitrate within 30 min into nitrogen and ammonium without pH control Preliminary experiments showed that the OBA nZVI has the low capacity to adsorb total dossolve solids TDS from the saline water while significant adsorption of hardness Ca2 Mg2 was observed with OBA nZVI In order to determine the most suitable model for describing the adsorption process of lead in batch experiment ANN ANFIS and MNLR models werer developed Five operational parameters including adsorbent dosage Cs initial concentration of Pb II ions Co initial pH temperature T and contact time t were taken as the input data and the adsorption efficiency AE of adsorbents as the output The comparison of models estimates showed that the ANFIS5 model which uses all input parameters had the best performance in prediction of AE The sensitivity analysis revealed that the estimated AE for OBA adsorbent is more sensitive to contact time followed by pH initial concentration of Pb II ions adsorbent dosage and temperature whereas PDF created with pdfFactory trial version www pdffactory com

اميري، محمد جواد

بهبود كيفيت آب آلوده به سرب، جيوه، نيترات و TDS با استفاده از خاكستر استخوان اصلاح شده توسط نانو ذرات آهن صفر ظرفيتي

كل مواد جامد محلول , جاذبOBA-nZVI