The bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) by the filter-feeding soft-shell clam Mya arenaria was evaluated at three sites near Boston (MA, USA) by assessing the chemical activities of those hydrophobic organic compounds (HOCs) in the sediment bed, water column, and organisms. Polyethylene samplers were deployed to measure the activities ...

In this work, zeolite 13X with porosity structure has been used as an adsorbent for adsorption of CO2 flue gas. The effect of operating conditions including pressure and time on adsorption capacity were investigated. The experiments conditions are constant temperature, the range of pressure 1 - 9 bar and the registration of adsorption capacity with passing of time. Experimental data were adjust...

In this work, the backward Bayesian multiple linear regression (BBMLR) as a new approach is presented to predict the adsorption efficiency (AE) of Cd(II) ions by ostrich bone char (OBC) in the fixed bed adsorption with four operational variables consisting of pH (2-9), inlet Cd(II) concentration (Co= 25-100 mg/L), bed depth (h= 3-9 cm) and feed flow rate (Q= 0.5-30 mL/min). The performance of t...

Heavy metals are serious pollutants in aquatic environments. A study was undertaken to remove Cu, Cd, Ni, Pb and Zn individually (single metal system) and together (mixed metals system) from water by adsorption onto a sodium titanate nanofibrous material. Langmuir adsorption capacities (mg/g) at 10(-3)M NaNO3 ionic strength in the single metal system were 60, 83, 115 and 149 for Ni, Zn, Cu, and...

the effect of hydraulic retention time in a range from 1.0-5.5 days was evaluated in a laboratoryscaleanaerobic fixed bed reactor packed with a hybrid material composed of tire rubber and zeolite. underthese conditions, cod removal efficiencies varied from 28.3% to 82.1%, respectively. over the more than 6months of operation, no clogging was observed. the results obtained demonstrated that this...

hydrogen was produced by steam reforming of dimethyl ether (dme) using a physical mixture of commercial hzsm-5 zeolite (for dme hydrolyzing) and cu/zno/al2o3 (for methanol steam reforming) as a catalyst in a fixed bed reactor. the experiments were performed at atmospheric pressure and in a temperature range from 270 to 310 °c. the effects of feed temperature and gas hourly space velocity (ghsv)...

operability analysis as one of the most important bridges between process design and process control helps the process designer to investigate the control issues quite early in the design stage. recently, vinson and georgakis suggested a steady state geometrical operability index as a quantitative measure for assessment of process operability. in this paper, dme fixed-bed reactor is heterogeneo...

a computational fluid dynamic (cfd) study of methanol (meoh) to dimethyl ether (dme) process in an adiabatic fixed-bed reactor is presented. one of the methods of industrial dme production is the catalytic dehydration of meoh. kinetic model was derived based on bercic rate. the parameters of this equation for a specific catalyst were tuned by solving a one-dimensional homogenous model using mat...

Natural Organic Matter (NOM) normally exists in raw surface water as a complex mixture of organic compounds, mainly humic acids and fulvic acids. In water treatment plants, free chlorine reacts with NOM and forms a wide range of substances known as Disinfection Byproducts (DBPs). Granular Activated Carbon (GAC) adsorption is one of the best available technologies employed for the removal of NOM...