Zehra Semra Can

Metal–organic frameworks (MOFs) with tunable structural and physicochemical properties are promising adsorbents for removing toxic metal ions from aqueous systems. However, the interplay among MOF characteristics, ion properties, and operating conditions complicates rational design and prediction. Here, we assemble a cross‐study dataset of 209 adsorption‐capacity measurements from ten peer‐reviewed studies, comprising experimental adsorption conditions (solution pH, initial concentration C ₀ , adsorbent dose), MOF‐specific properties (Brunauer‐Emmett‐Teller (BET) surface area, pore size, pore volume, pH _pzc ), and pollutant‐specific properties (oxidation state, atomic mass, electronegativity, ionization energy, atomic radius). Four machine‐learning regressors were trained and evaluated; XGBoost achieved the best performance ( R ² _train = 0.9999, R ² _test = 0.9513). Model interpretability using Shapley additive explanations (SHAP) identified C ₀ as the dominant factor, followed by solution pH in relation to pH _pzc ; BET surface area and pore size also contributed substantially, while oxidation state and atomic mass had moderate effects. Collectively, these results demonstrate that interpretable machine learning can uncover governing factors in MOF–ion adsorption and provide practical design rules for tuning operating conditions and selecting MOFs for metal‐ion removal from water.

In this work, we present a process for converting olive industry solid waste (OISW) into a value-added material with ionic receptors for use in the removal of toxic metal ions from wastewater. This 3D polymer is a promising adsorbent for large-scale application, since it is a low-cost material made from agricultural waste and showed exceptional performance. The synthesis of the network polymer involved the carboxymethylation of OISW and curing of the carboxymethylated OISW at an elevated temperature to promote the formation of ester linkages between OISW’s components. FT-IR, atomic force microscopy, and thermal analysis were performed on the crosslinked product. The adsorption efficiency of the crosslinked carboxymethylated OISW toward Pb(II), Cu(II), and other toxic metal ions present in sewage was evaluated as a function of adsorbent dose, temperature, pH, time, and initial metal ion. The percentage removal of about 20 metal ions present in a sewage sample collected from a sewer plant located in the Palestinian Territories was determined. The adsorption efficiency did not drop even after six cycles of use. The kinetic study showed that the adsorption process follows the Langmuir isotherm model and the second-order adsorption rate. The experimental Qe values of 13.91 and 13.71 mg/g were obtained for Pb(II) and Cu(II) removal, respectively. The thermodynamic results confirm the spontaneous metal bonding to the receptor sites of the crosslinked carboxymethylated OISW.

Ozone is used as an oxidant and disinfectant in water treatment practices. However, partial oxidation of natural organic material (NOM) by ozone produces oxygenated by-products of low molecular weight, such as formaldehyde. Formaldehyde is considered as problematic compounds by the water industry due to their potential adverse health effects. The main objective of this study is to investigate the kinetics and mechanism of formaldehyde formation from NOM. Humic material was used as NOM model, mainly because humic material is the major constituent of dissolved organic matter in natural waters, and may be the primary source of precursor material for aldehydes. This research attempts to provide specific information on the effect of water quality parameters, specifically, pH and alkalinity, and different sources of humic material on generation of formaldehyde. The results showed that formaldehyde started to form upon ozonation of humic and fulvic acids, reached a peak value after 20-30 minutes of ozonation under the experimental conditions, and then started to decrease with continued ozonation. The interaction of ozone with aqueous based fulvic acid produced higher concentrations of formaldehyde compared to different types of humic acids. Formaldehyde formation was not affected significantly by bicarbonate ion within the concentration range of 0.5 mM and 2 mM, but less formaldehyde was produced in the presence of 6 mM bicarbonate. Formaldehyde accumulated faster at pH 8.5 than at pH 5.8. Formaldehyde formation was hindered in the presence of Br-. It was also observed that formaldehyde after formation went through further oxidation to form formic acid and subsequently carbon dioxide. In order to understand the mechanism and the kinetics of the chemical reactions that lead to the formation and oxidation of formaldehyde during ozonation, pure solutions of formaldehyde and formic acid were ozonated in batch reactors. Experimental data were used to test the proposed mechanistic and kinetic models developed for oxidation of formaldehyde and formic acid. After successful verification, these models were expanded to an overall model to predict formaldehyde formation from humic material. Formaldehyde formation in four different synthetic solutions of fulvic and humic acids, and one natural water sample was predicted fairly well by the overall model.

Nonylphenol (NP) and octylphenol (OP) are considered as endocrine disrupting compounds and they restrict the reuse potential of wastewater. Therefore, innovative and reliable technologies are required for elimination of these compounds from waste streams. In this study, we consider use of iron nanoparticles (nZVI) (0.1 mM; 2 mM) and also a composite of nZVI/fullerene nanoparticles (aq-nC₆₀) (0.1 mM nZVI/2.5 ppm aq-nC₆₀; 2 mM nZVI/2.5 ppm aq-nC₆₀) for the removal of 25 μg/L NP and OP concentrations. The nano-composite was synthesized according to chemical reduction method and was characterized using XRD, particle size distribution and zeta potential measurements. NP and OP concentrations were quantified with a GC-MS. The results demonstrated that 0.1 mM nZVI alone resulted in 6% and 17% decrease in NP and OP concentrations, respectively. However, when the nZVI concentration was increased to 2 mM, the removal efficiency increased to 59% for NP and 32% for OP. When compared with NP, lower removal rates were achieved for OP regardless of the nZVI concentration. Although NP and OP have similar chemical structures, OP has a branched arrangement and this structure is anticipated to cause a decrease in the active adsorption sites and lower removal efficiency for OP. Highest removal was obtained with 0.1 mM nZVI/2.5 ppm aq-nC₆₀ for both NP and OP. Our results show that nZVI/aq-nC₆₀ holds a potential for elimination of NP and OP from wastewater sources.

Endocrine-disrupting compounds (EDCs) are exogenous substances that cause adverse health effects in an intact organism, or its progeny, subsequent to the changes in endocrine function. Recent studies have shown that wastewater treatment plant effluents play an important role in the release of EDCs into aquatic environments. Therefore, in this study, influent and effluent samples from three different wastewater treatment plants (WWTPs) in Istanbul were analysed for the presence of the principal EDCs. These chemicals include steroids and synthetic organic chemicals. Thus, the occurrence and fate of EDCs of great health concern were monitored at three WWTPs in Istanbul. Furthermore, these WWTPs are employing different treatment processes. Therefore, the EDC removal performances of different treatment regimes were also evaluated. Phytosterol was the most abundant EDC in the influent samples. Second group of compounds at high influent levels were alkyl phenols. Pesticide levels of all three WWTP influent samples were low. Pasakoy Advanced WWTP is more effective at eliminating EDCs. Kadikoy Primary WWTP exhibits the lowest EDC elimination efficiencies. To the best of our knowledge, this work comprises the first detailed report on the occurrence and behaviour of both natural and synthetic EDCs in WWTPs of Istanbul and Turkey. The steroid estrogen levels of this study are higher than the previously documented values, except the levels given for Gaobeidian WWTP in Beijing, China. This is attributed to higher population densities of Beijing and Istanbul and as well as to lower individual water consumption rates in the two cities.

Effluent from the Paşaköy Wastewater Treatment Plant was oxidized by using O₃ and O₃/H₂O₂. DOC, COD, UV₂₅₄, total coliform, dissolved ozone and some endocrine disrupting compounds were monitored during oxidation. Results showed that O₃ provided superior disinfection, however, lower reductions in DOC, COD and endocrine disrupting compounds were exhibited compared to O₃/H₂O_2. The highest removal efficiency of DOC, COD and endocrine disrupting compounds were achieved at 0.5 molar ratio of O₃/H₂O_2. The benefit of H₂O₂ addition for advanced oxidation reduced significantly when the mole ratio was increased to 2. Therefore, the mole ratio of H₂O₂ to O₃ is a critical parameter for the design of wastewater oxidation by O₃/H₂O₂.