No abstract

No abstract

Dehydration technique with 80% sulfuric acid was used to create a novel biochar from mandarin peel wastes followed by condensate with triethylenetetramine (TETA) to give Mandarin Biochar-TETA (MBT). BJH, BET, FTIR, SEM, DSC, TGA, and EDX studies were used to characterise the MBT. The capacity of the newly developed biochar to remove Acid Yellow 11 (AY11) dye from a water solution was studied. The pH of AY11 dye adsorption was found to be best at pH 1.5. Using 100 ppm AY11 dye as a beginning concentration and 1.75 g L–1 MBT dose, the greatest percent of AY11 dye removal by MBT was 97.83%. The MBT calculated maximum adsorption capacity (Qm) was 384.62 mg g–1. Langmuir (LIM), Freundlich (FIM), Tempkin (TIM), and Dubinin–Radushkevich (DRIM) isotherm models were applied to analyse the experimental data. Furthermore, the results of these isotherm models were investigated by various known error function equations. The MBT experimental data was best suited by the LIM. Pseudo-first-order (PFO), pseudo-second-order (PSO), Elovich kinetic model (EKM), intraparticle diffusion (IPD), and film diffusion (FD) models were used to calculate kinetic data. A PSO rate model with a high correlation (R2 > 0.990) was used to assess the adsorption rate. The main mechanism of the MBT adsorption method of the AY11 dye’s anions adsorption is the electrostatic attractive forces that arise with the increase of positively charged sites in an acidic medium. The obtained data suggest that the prepared MBT adsorbent has the potential to be an effective material to remove the AY11 dye from water and that it may be used repeatedly without losing its adsorption efficiency.

No abstract

T he concentrations of certain heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pd and Zn) in the total and labile fractions of muddy sediment samples collected from eleven sites in Lake Burullus in January 2003 were investigated in order to evaluate the pollution status of the Lake. The metal contents were determined by means of Atomic Absorption Spectrophotometer (AAS) using MESS-2 certified reference material (National Research Council of Canada). The average concentrations of the heavy metals analyzed in total sediment fractions exhibited the following decreasing order: Fe > Mn > Cu > Ni > Zn > Cr > Pb > Co > Cd, while the average concentrations of the heavy metals analyzed in the labile fraction followed the order: Fe > Mn > Cu > Ni > Pb > Zn > Co > Cr > Cd. The concentrations of all studied heavy metals ranged between the Effect Range-Low (ERL) and the Effect Range-Median (ERM) for most studied locations. Metal pollution index (MPI) shows very high values for both total and labile fractions at all the examined locations. Field observation reveals that Lake Burullus received industrial, agricultural and domestic sewage, suggesting that anthropogenic input is the main source of heavy metal contamination. Health hazard calculations for the contaminated sediments exhibited a possibility,pf health risk due to long-term exposure of the human to the polluted sediments of Lake Burullus.