Monitoring of salt iodisation programme in Iran; Health outcomes, shortages and perspective

Iodine deficiency disorders include a wide range of metabolic and nonmetabolic disorders including goiter. To control IDDs, the World Health Organization and responsible agencies in countries established daily iodine uptake. Almost all the countries in the world provide the required iodine through salt iodisation. IDDs are not completely eradicable, so monitoring the salt iodisation programme is necessary for control of IDDs. In Iran, a salt iodisation programme was started in 1996. In this study, we took salt samples from all legally produced salt brands in Iran in 30 provinces and measured iodine concentration. The results of the monitoring programme for iodine concentration in schoolchildren's urine was used to compare accessibility to iodized salts and health outcomes. The results show that more than 80 of available salts have a suitable or acceptable concentration of iodine. Despite large variance in iodine concentration in available salt in some provinces, the median of iodine concentration in salts is within an acceptable range. Also, the urinary concentration of iodine (national median = 161) confirms that shortage of iodine intake is very low in Iran. The high rate of salt consumption of the Iranian people also has a significant effect on iodine uptake, but can lead to hyperthyroidism and hypertension that must be controlled. © 2018 Elsevier Gmb

Designed synthesis of perylene diimide-based supramolecular heterojunction with g-C3N4@MIL-125(Ti): insight into photocatalytic performance and mechanism

A new supramolecular semiconductor perylene diimide (PDI)-functionalized g-C3N4@MIL-125(Ti) (is nominated as PC@MIL-125(Ti)) was prepared through in situ growth of MIL-125(Ti) on PDI-functionalized g-C3N4 (PC) sheets. This heterojunction was used for photodegradation of methyl orange (MO) pollutants under visible light illumination. This process was sensitive to the pH of solution, dosage of PC and the presence of the various scavengers. The 30PC@MIL-125(Ti) as optimum photocatalyst indicated synergistic effects on photodegradation of MO, where the maximum photocatalytic efficiency was obtained 100 under 90 min irradiation that was higher than pure PC and MIL-125(Ti). Herein, the PDI component acts as a powerful light harvester and improves absorption of visible light where PC@MIL-125(Ti) has a lower bandgap than g-C3N4@MIL-125(Ti). Moreover, proper contact between PDI and g-C3N4 sheets constructs the highway for easy and fast electron transfer that verified by photoluminescence analysis. The sum of these factors resulted in the superior photocatalytic ability of this heterojunction, where the TOC analysis confirmed 91 mineralization for MO. Besides, according to the results of LC-MASS analysis, the azo cleavage and dealkylation were main photodegradation pathways. By considering superior photocatalytic performance of this heterojunction, this work can be a guideline for the development of PDI-based supramolecular organic�inorganic photocatalyst. © 2021, Springer Science+Business Media, LLC, part of Springer Nature

Design and preparation of core-shell structured magnetic graphene oxide@MIL-101(Fe): Photocatalysis under shell to remove diazinon and atrazine pesticides

A magnetically separable support with core-shell morphology comprising amine-functionalized Fe3O4 wrapped with graphene oxide (AFG) was successfully prepared and used to support MIL-101(Fe). The ternary AFG@MIL-101(Fe) composite was investigated as a photo-Fenton catalyst for the degradation of recalcitrant diazinon (DIZ) and atrazine (ATZ) pesticides. After 105 min visible light irradiation, the AFG@30MIL-101(Fe) photocatalyst achieved 100 ± 1 and 81 ± 1 photocatalytic degradation efficiency for DIZ and ATZ pollutants, respectively. The recorded data indicated superior photocatalytic ability of the nanocomposite as compared to AF@30MIL-101(Fe) and MIL-101(Fe) photocatalysts for the removal of both pollutants. Total Organic Carbon (TOC) analysis revealed 84 ± 0.5 and 62 ± 0.5 mineralization for DIZ and ATZ, respectively. The obtained results of characterization and also photocatalytic behavior suggest enhanced conversion between Fe2+/Fe3+ as well as fast electron transfer through interlayers of graphene oxide in this unique core-shell structure. After assaying the adsorption performance of photocatalyst, it was found that ATZ adsorption was more pronounced than DIZ. Furthermore, radical quenching tests revealed radOH radicals were the main oxidizing players in this process even though the contribution of other species cannot be ruled out. It is noteworthy that magnetic stability was well preserved after 4 consecutive photocatalytic cycles, suggesting that this work can be a guideline to prepare efficient and stable magnetic Fenton systems. © 2020 International Solar Energy Societ

Methods for preparation and activation of activated carbon: a review

Activated carbon refers to a wide range of carbonised materials of high degree of porosity and high surface area. Activated carbon has many applications in the environment and industry for the removal, retrieval, separation and modification of various compounds in liquid and gas phases. Selection of the chemical activator agent is a major step controlling the performance and applicability of activated carbon. Here, we review chemical activators used to produce activated carbon. We compare the impregnation method with the physical mixing method used in activating with alkali hydroxides. We selected 81 articles from Google Scholar, PubMed, Scopus, Science Direct, Embase and Medlin databases. Eighteen articles report the activation with potassium hydroxide, 17 with phosphoric acid, 15 with zinc chloride, 11 with potassium carbonate, nine with sodium hydroxide, and 11 with new activating agents. Activation with phosphoric acid is commonly used for lignocellulosic material and at lower temperatures. Zinc chloride generates more surface area than phosphoric acid but is used less due to environmental concerns. Potassium carbonate, in comparison with potassium hydroxide, produces higher yields and a higher surface area for the adsorption of large pollutant molecules such as dyes. Activating with potassium hydroxide in terms of surface area and efficiency shows better results than sodium hydroxide for various applications. Also, the comparison of the physical mixing method and the impregnation method in activation with alkali metals indicates that the activated carbon obtained through physical mixing had a higher porosity than the activated carbon produced by the impregnation method. © 2020, Springer Nature Switzerland AG

Preparation of tungstophosphoric acid/cerium-doped NH2-UiO-66 Z-scheme photocatalyst: a new candidate for green photo-oxidation of dibenzothiophene and quinoline using molecular oxygen as the oxidant

The goal of this study was to introduce an effective visible-light induced photocatalytic system with a good ability for photocatalytic oxidative desulfurization (PODS) and denitrogenation (PODN) using molecular oxygen (O2) as an oxidant. In this regard, tungestophosphoric acid (PW12) was supported onto cerium-doped NH2-UiO-66 (PW12/Ce-NUiO-66) and employed for the photo-oxidation of dibenzothiophene (DBT) and quinoline (Qu). Herein, using cerium (Ce) as a �mediator� facilitated the separation of charge carriers, while NH2-UiO-66 remarkably enhanced the surface area with plentiful adsorption sites and shifted the adsorption edge of PW12to the visible region. The sum of these factors resulted in superior photocatalytic ability and maximum efficiency of 99 ± 1 was achieved by using 30PW12/Ce-NUiO-66 as the optimum photocatalyst in the PODN system and 89 ± 1 in the PODS system under visible light irradiation for 90 min. The traditional Z-scheme mechanism was proposed as the main pathway for this photocatalytic system. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2021

Assessment of the health risk and geo-accumulation of toxic metals in agricultural soil and wheat, northern Iran

The current work was conducted to study the concentrations of heavy metals (HMs) in farming soil and wheat and compute their geological and health indexes, including geo-accumulation index (Igeo), chronic daily intake (CDI), hazard index (HI), hazard quotient (HQ), and cancer risk (CR). In general, 256 samples were collected from agriculture soil (AS) and wheat in Kalaleh and Aq Qala areas, northern Iran. The average rates of Cd, Cu, Pb, and Zn were detected to be 0.28, 25.24, 15.44, and 60.33 mg·kg�1, respectively, for AS and 0.01, 8.85, 0.73, and 33.81 mg·kg�1 for wheat, respectively. Based on the results, the HQ and HI levels for investigated HMs were lower than l. So, the health risk of HMs exposure for adults and children was low. CR levels for Pb in AS for both children and adults were observed greater than the threshold value. Accordingly, lead-contaminated soil will be carcinogenic if ingested by children. On the other hand, the exposure to Pb (through wheat) and Cd (through both soil and wheat) had the acceptable CR level for all groups. As a result, for an extended period, there are no significant health consequences for children and adults. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG

Photocatalytic degradation of malathion using Zn2+-doped TiO2 nanoparticles: statistical analysis and optimization of operating parameters

A Zn2+-doped TiO2 is successfully synthesized by a facile photodeposition method and used in the catalytic photo-degradation of organophosphorus pesticide, malathion. The obtained photocatalysts are characterized in detail by X-ray diffraction (XRD), Brunauer�Emmett�Teller (BET), Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). XRD results confirm the formation of the anatase and rutile phases for the Zn2+-doped TiO2 nanoparticles, with crystallite sizes of 12.9 nm. Zn2+-doped TiO2 that was synthesized by 3.0wt Zn doping at 200 °C exhibited the best photocatalytic activity. 60 sets of experiments were conducted using response surface methodology (RSM) by adjusting five operating parameters, i.e. initial malathion concentration, catalyst dose, pH, reaction time at five levels and presence or absence of UV light. The analysis revealed that all considered parameters are significant in the degradation process in their linear terms. The optimum values of the variables were found to be 177.59 mg/L, 0.99 g/L, 10.99 and 81.04 min for initial malathion concentration, catalyst dose, pH and reaction time, respectively, under UV irradiation (UV ON). Under the optimized conditions, the experimental values of degradation and mineralization were 98 and 74, respectively. Moreover, the effects of competing anions and H2O2 on photocatalyst process were also investigated. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature

Photocatalytic degradation of malathion using Zn2+-doped TiO2 nanoparticles: statistical analysis and optimization of operating parameters

A Zn2+-doped TiO2 is successfully synthesized by a facile photodeposition method and used in the catalytic photo-degradation of organophosphorus pesticide, malathion. The obtained photocatalysts are characterized in detail by X-ray diffraction (XRD), Brunauer�Emmett�Teller (BET), Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). XRD results confirm the formation of the anatase and rutile phases for the Zn2+-doped TiO2 nanoparticles, with crystallite sizes of 12.9 nm. Zn2+-doped TiO2 that was synthesized by 3.0wt Zn doping at 200 °C exhibited the best photocatalytic activity. 60 sets of experiments were conducted using response surface methodology (RSM) by adjusting five operating parameters, i.e. initial malathion concentration, catalyst dose, pH, reaction time at five levels and presence or absence of UV light. The analysis revealed that all considered parameters are significant in the degradation process in their linear terms. The optimum values of the variables were found to be 177.59 mg/L, 0.99 g/L, 10.99 and 81.04 min for initial malathion concentration, catalyst dose, pH and reaction time, respectively, under UV irradiation (UV ON). Under the optimized conditions, the experimental values of degradation and mineralization were 98 and 74, respectively. Moreover, the effects of competing anions and H2O2 on photocatalyst process were also investigated. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature