Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 2019

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Utilization of Calcined Gypsum in Water and Wastewater Treatment: Removal of Phenol

Igwegbe Chinenye Adaobi, Al-Rawajfeh Aiman Eid, Al-Itawi H.I., Sharadqah S., Al-Qazaqi Shahd, Abu Hashish Esraa, Al-Qatatsheh Malak, Sillanpaa Mika

Journal of Ecological Engineering

2019

Vol. 20, nr 7

1--10

The release of phenol-containing effluents above the phenol permissible limit has triggered a lot of concern over the world due to their toxic nature. The adsorptive potential of gypsum on the removal of phenol was investigated. The effect of gypsum loading (0.5–3 g), contact time (2.5–20 min) and solution temperature (298 to 318 K) on the removal of phenol by gypsum was studied at neutral pH. The thermodynamics of the adsorption process was also studied. The kinetic data were fitted into the pseudo-second-order, Elovich, and intraparticle diffusion models. The removal efficiency of phenol increased along with the mass of gypsum, contact time and temperature. The results of the thermodynamics study indicate that the adsorption process is spontaneous and endothermic in nature. The change in free energy (ΔG0) was found to increase with temperature. The values of the estimated ΔG0 suggest that the phenol adsorption on gypsum is a physical adsorption process. Additionally, the kinetic data fitted best into the pseudo-second-order than the other kinetic models. This study proved that phenol can be used effectively for the reduction of phenol concentrations in water and wastewater.

Mitigation of scale problem in the pumped Disi water to Amman, Jordan

Al-Maabreh Alaa M., Al-Rawajfeh Aiman Eid, Alshamaileh Ehab, Al-Bazedi G. A.

Environment Protection Engineering

2019

Vol. 45, nr 1

97--110

Various methods are known to mitigate or prevent scale formation in pipes, rather by chemical addition, e.g., anti-scaling substances, or physically which includes ultrasonic or nanofiltration (NF). Nanofiltration membranes have a selectivity for the multivalent charged ions, so monovalent ions will pass the membrane partly and multivalent ions will be rejected completely. Chemical addition to prevent scale formation is based on justifying water parameters such as pH, alkalinity, and concentrations of ions that form the building units of scale crystal. In order to mitigate the scaling tendency in water pumped from the Disi aquifer to Amman city along its 345 km pipeline, different studies were conducted using simulated plumbing system. This part of the study is concerned with scale mitigation using nanofiltration and addition of chemicals. Nanofiltration was applied to reduce the hardness that causes scale deposition where it rejected around 70.5% of Ca2+, 71.98% Mg2+, 7.72% K+, 29.0% Na+, 66.63% Cl–, 86.51% NO3 – , 85.72% SO4 2–, and 69.85% CO2. Increasing the concentration of some ions such as Na+, K+ and Cl– keeping the allowable limit gave good results for scale mitigation.