الفهرس 
ABSTRACTOnly 14 pages are availabe for public view
 |  | from | 94 |  |  |
| | | from | 94 | | |
Abstract
Biomass-derived adsorbents are widely used, due to the significant advantages of easy scale up, cost efficiency and environmental friendly. The preparation of bio-adsorbents which are economically and environmentally sustainable has achieved an enormous interest in waste water treatment .The aim of present work is divided into two stages. The first one is preparation of high-capacity adsorbent from barely straw (BS) and coconut shell (CS) by applying single step method using sulfuric acid ,and the second is utilization of bio-adsorbents in removal of methylene blue (MB) dye from wastewater. Response Surface Methodology Model was applied to predict the optimum parameters for production of the bio-adsorbent. Two parameters were selected in preparation of bio-adsorbent (time, 1-3 h; H2SO4 concentration, 82-98%; liquid/solid (L/S) ratio, 4-12 ml/g). The optimal conditions for the sulfuric acid refluxing stage were obtained at 94 % sulfuric acid, 10 L/S ratio for 2 h, and 98% sulfuric acid, 4 L/S ratio for 2.5 h for BS and CS, respectively. The produced bio-adsorbent were characterized by scanning electron microscopy coupled with energy dispersive X-ray scattering, X-ray diffraction, Fourier transform infrared spectroscopy, Thermo gravimetric analysis, Raman spectroscopy and the Brunauer–Emmett–Teller specific surface area analysis. The detailed analyses showed that the bio-adsorbent produced from BS and CS have good adsorptive properties, thermal stability and high specific surface area which are 1.165 and 11.759 m2/g, respectively. Then, they are used as bio-adsorbent to eliminate methylene blue (MB) from wastewater. Several parameters are studied such as pH (3.5-13.5) and initial concentration of dye in wastewater (100-500) ppm, and it is found that the adsorption capacity is improved in the basic medium; also, it is directly proportional to the initial concentration .Different adsorption isotherm were studied ( Langmuir ,and Freundlich ) . It was found that the adsorption process more fitted with Langmuir isotherm than the Freundlich isotherm for both adsorbents, so it confirmed that the adsorption process is monolayer. The adsorption kinetics were investigated by pseudo-first-order and pseudo- second-order models, and the pseudo-second-order kinetic model was in best fit with the experimental results. The maximum adsorption capacity was found to be 256.4, and 344.8 mg/g for barley straw and coconut shell respectively, and in the 3rd part design parameters of packed bed column were calculated for batch adsorption process.