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The Removal of Phenol Through Adsorption onto Synthetic Calcium Phosphates – A Study Encompassing Analyses of Kinetics and Thermodynamics

El Bakri Abdellatif, El Boujaady Hicham, Ferraa Nouhaila, Bennani-Ziatni Mounia

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 4

301--315

EN

The characteristics and suitability of hydroxyapatite (HAP), tricalcium apatite phosphate (PTCa), and octocalcium apatite phosphate (OCPa), which possess similar attributes to those of an ideal adsorbent, were investigated to determine their efficacy in phenol removal. The aim of this paper is to assess the adsorption behavior of phenol on phosphates powders synthesized by the co-precipitation method at ambient temperature. Furthermore, the impact of initial phenol quantities and thermal conditions on the adsorption process was explored. X-ray diffraction analysis revealed the formation of HAP, PTCa, and OCPa structures under room temperature conditions. The sample morphologies were subjected to scrutiny utilizing MEB together with X-ray analysis. Additionally, chemical analysis revealed that Ca/P = 1.6, 1.5, and 1.33 for HAP, PTCa, and OCPa, respectively. The synthesized powders exhibited adsorption abilities of 2.86, 2.74, and 2.52 mg/g for HAP, PTCa, and OCPa, respectively, and reached equilibrium in approximately 80 minutes. The study revealed that the experimental data are appropriately represented by the Langmuir and Freundlich adsorption equations for HAP and PTCa, and Langmuir model in the case of OCPa, as well as by the pseudo-first-order and pseudo-second-order adsorption kinetics. Thermodynamic evaluations, including calculations of ΔG°, ΔH°, and ΔS°, were performed. The results indicated that the adsorption mechanisms exhibited physical characteristics, were thermally absorbing in the case of HAP and exothermic for the other two phosphates, PTCa and OCPa, and occurred spontaneously.

2

Optimization of induced crystallization reaction in a novel process of nutrients removal coupled with phosphorus recovery from domestic wastewater

Zou H., Wang Y.

Archives of Environmental Protection

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2017

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Vol. 43, no. 4

33--38

EN

Phosphorus removal and recovery from domestic wastewater is urgent nowadays. A novel process of nutrients removal coupled with phosphorus recovery from domestic sewage was proposed and optimization of induced crystallization reaction was performed in this study. The results showed that 92.3% of phosphorus recovery via induced Hydroxyapatite crystallization was achieved at the optimum process parameters: reaction time of 80 min, seed crystal loads of 60 g/L, pH of 8.5, Ca/P mole ratio of 2.0 and 4.0 L/min aeration rate when the PO43-P concentration was 10 mg/L in the influent, displaying an excellent phosphorus recovery performance. Importantly, it was found that the effect of reaction temperature on induced Hydroxyapatite crystallization was slight, thus favoring practical application of phosphorus recovery method described in this study. From these results, the proposed method of induced HAP crystallization to recover phosphorus combined with nutrients removal can be an economical and effective technology, probably favoring the water pollution control and phosphate rock recycle.

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Wykorzystanie platform telekomunikacyjnych HAP i VSAT w zarządzaniu sytuacjami kryzysowymi

Wilczewski G., Walewski P.

Logistyka

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2015

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nr 4

8503--8510, CD2, cz. 5

PL

W artykule przedstawiono analizę technik platform stratosferycznych (ang.: HAP – High Altitude Platform) oraz VSAT (ang.: Very Small Aperture Terminal) pod względem możliwości dostarczania łączności na potrzeby służb ratowniczych na obszarach dotkniętych kataklizmem. W ramach opisywanego systemu jako trzy podstawowe strony komunikacji określono: ratowników, Polowe Centrum Zarządzania i Szpital Polowy Utworzono zestawienie prezentujące relacje komunikacyjne pomiędzy tymi jednostkami. Wyznaczone zostały także usługi, które znalazłyby swoje zastosowanie wspierając systemy zarządzania w sytuacjach kryzysowych. Określono również wymagania systemowe dotyczące tych usług. Obie techniki zostały porównane pod względem możliwości dostarczania wyszczególnionych usług, w należytej jakości. Oszacowano także wartości maksymalne liczby obsługiwanych użytkowników końcowych. Zaprezentowano również zestawienie numeryczne minimalnych czasów potrzebnych na pobranie rzeczywistych wyników badań z bazy danych.

EN

The article presents thorough analysis of telecommunication platforms of HAP (High Altitude Platform) and VSAT (Very Small Aperture Terminal) technologies, as to indicate which of these is more capable and applicable for crisis management systems that require reliable, mobile and high capacity solutions. Rescuers, Field Management Center and Field Hospital were defined as the three main communication parties, creating juxtaposition of relations in between. The set of telecommunication services supporting crisis management systems was determined along with the specific QoS requirements. Both techniques, HAP and VSAT, have been compared with respect to the delivery capabilities of the selected services with appropriate quality. Assessment of the crucial parameters of both systems: maximum count of end-users being served alongside the volume of the traffic contributing to the specific type of medical data was performed. Finally, evaluation of capabilities in the fastest delivery of the selected medical reports was assessed.

4

High Altitude Platform : Future of Infrastructure

Malinowski A., Zieliński R. J.

International Journal of Electronics and Telecommunications

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2010

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Vol. 56, No. 2

191-196

EN

High Altitude Platform (HAP) concept and idea is presented in the article. Characteristics, advantages and disadvantages of HAPs are described. There is also the comparison available between HAPs and existing telecommunication infrastructure (terrestrial and satellite). Selected examples of the possible limitation and technological restrictions of HAP based systems are presented in the article.