z Materials Science inc. Nanomaterials & Polymers Mesoporous Organic–Inorganic Core–Shell Necklace Cages for Potentially Capturing Cd 2 + Ions from Water Sources Abdel-Aty E. Soliman, [a, b] Mohamed A. Shenashen,* [a] Islam M. El-Sewify, [a] Gharib M. Taha, [b] Mahmoud. A. El-Taher, [b] Hitoshi Yamaguchi, [a] Ahmad S. Alamoudi, [c] Mahmoud M. Selim, [d] and Sherif A. El-Safty* [a] Dedicated this research work to Mr. Solimans memory We report the one-pot synthesis of ball-like nanosphere structures composed of an a-Fe core and an organic shell of ethylenediaminetetraacetic acid that connected together to form a nanochain necklace-like morphology. The hierarchical zigzag nanochain sphere structures have branches growing in clumps, a large surface area, and spherical pore-like cages and entrances for capture/trapping Cd 2 + ions from water sources. The pH solution (i.e., at pH 5) plays a key role in the generation of actively negative surfaces along the entire nanochain sphere adsorbent, thereby creating surfaces with strong binding affinity to Cd 2 + ions. The thermodynamic and kinetic character- istics indicated that the nanochain sphere adsorbent with macro- and meso-cage caves and organically decorated surfaces show promise for the spontaneous and endothermic capturing of Cd 2 + ion containments from water solutions. The zigzag nanochain mesoporous necklace-like structure trapper (MNT) exhibited long-term stability, indicating that it can be used several times (reduced waste volume). The adsorption efficiency and uptake of the deleterious Cd 2 + ions retained even after multi-particulate processing of reuse cycles. The pH- dependent Cd 2 + ion selectivity indicated high adsorption capacity (526.3 mg·g À1 ) and Cd 2 + ion-to-MNT binding affinity, despite the addition of interfering cations or anions. The zigzag nanochain sphere necklace allows the development of a simple and effective adsorbent model for water purification and management of toxins. Introduction After industrial growth, technological innovation, and econom- ic advancements, the production of massive amounts of hazardous inorganic pollutants (heavy metals) to the environ- ment had rapidly increased worldwide. Heavy metals are naturally found in the earth and are considered the major source of various water source pollutants. Capturing toxic metal ions from environmental samples is the most demanding and vital field in analytical and environmental chemistry. [1,2] Cadmium is an extremely toxic heavy metal that signifi- cantly contaminates both soil and water. This metal is used extensively in manufacturing procedures as an anticorrosive agent, a stabilizer in PVC products, and a color pigment, and is also used in phosphate fertilizers that show huge cadmium loads. Much of the cadmium pollution has occurred by deposition and incinerating cadmium-polluted waste. [3] Further- more, mining, metallurgy, electroplating processes, batteries, accumulator fabrication processes, pigments, ceramics indus- tries, and production of paints release undesirable amounts of Cd 2 + ions. [4–6] This metal can easily enter the human body via food chains [7] because it can accumulate in the growing plant’s tissues in industrially contaminated areas. Moreover, cadmium (Cd +2 ) has been classified as a human carcinogen and teratogen that affects the lungs, kidneys, liver, and reproductive organs. [8,9] The World Health Organization set the allowable level for cadmium in drinking water at 3 mg/L. [10] The trapping of cadmium ions from drinking water is viewed as one of the indispensable issues that scientists worldwide seek to resolve, thereby saving the environment from excessive cadmium release. Researchers have proposed different physical and chemical approaches, such as chemical sensors coagulation, reverse osmosis, precipitation, adsorption, [a] A.-A. E. Soliman, Dr. M. A. Shenashen, I. M. El-Sewify, Dr. H. Yamaguchi, Prof. S. A. El-Safty National Institute for Materials Science (NIMS) 1-2-1 Sengen, Tsukuba-shi, Ibaraki-ken, 305-0047 (Japan) E-mail: SHENASHEN.Mohameda@nims.go.jp Sherif.ELSAFTY@nims.go.jp [b] A.-A. E. Soliman, Prof. G. M. Taha, Prof. M. A. El-Taher Environ. Applications of Nanomaterials Lab., Chemistry Department, Faculty of Science, Aswan University, Aswan, 81528, Egypt. [c] Dr. A. S. Alamoudi Desalination Technologies Research Institute (DTRI), Al-Jubail, 31951 Saudi Arabia. [d] Prof. M. M. Selim Department of Mathematics, Al-Aflaj College of Science and Human Studies, Prince Sattam Bin Abdulaziz University, Al-Aflaj 710-11912, Saudi Arabia. Supporting information for this article is available on the WWW under https://doi.org/10.1002/slct.201701247 Full Papers DOI: 10.1002/slct.201701247 6135 ChemistrySelect 2017, 2, 6135 – 6142  2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim