Editorial for Special Issue “Recent Advances in Photocatalytic Treatment of Pollutants in Water”

Abatement vs. treatment for efficient diffuse source water pollution management in terrestrial-marine systems.

Qu, G.J., 2020. An evaluation method for water pollution treatment efficiency in coastal cities based on regional management. In: Al-Tarawneh, O. and Megahed, A. (eds.), Recent Developments of Port, Marine, and Ocean Engineering. Journal of Coastal Research, Special Issue No. 110, pp. 100–103. Coconut Creek (Florida), ISSN 0749-0208.At present, coastal cities are constantly enhancing their water pollution treatment capabilities, so how to evaluate the efficiency of water pollution treatment is very important. This paper takes Shenzhen as an example to analyze the current status of the water pollution in Shenzhen city, China; first, it adopts the model of data envelopment analysis (DEA model) to measure the water pollution treatment efficiency; then the paper applies the Tobit model to conduct regression analysis on the influencing factors of water pollution treatment efficiency in coastal cities. The research results show that there are serious water pollution problems in coastal cities across the country. The central government and local governments attach great importance to water pollution treatment, and have invested a lot in coastal cities for this. With the increasing investment in water pollution treatment in coastal cities, the treatment capability and related systems have been improved further, and the water pollution treatment works have achieved certain results. Economic level, population density, and urbanization rate can positively affect the efficiency of water pollution treatment in coastal cities, and the industrial structure and the degree of opening up can adversely affect the efficiency of water pollution treatment in coastal cities. This paper aims to play a role in promoting the efficiency of water pollution treatment in coastal cities.

Review on the treatment of organic pollutants in water by ultrasonic technology

Efficient treatment of organic pollutants in water by a facile and green technique is a great challenge for environmental remediation. In this study, we report a simple and low-energy strategy for catalytic reduction of organic pollutants in water by continuous-flow flash nanoprecipitation. The one-step processing technique integrates rapid metal@polymer nanoparticle production and catalytic reaction in a continuous-flow fashion. Such a concept is successfully demonstrated for simultaneous formation of Au@polymer nanospheres and catalytic reduction of organic pollutants (e.g., methylene blue and 4-nitrophenol) in water. Furthermore, the catalytic reaction rate could be easily tuned by varying the processing parameters (e.g., feeding concentration). The activity of the nanocatalyst was demonstrated in five recycles without any detectable loss. The characteristics of continuous-flow mode make the one-step process scalable, promising processing methodology for wastewater treatment.

Efficient treatment and utilization of organic pollutants in water are difficult for environmental remediation. A new hyper-cross-linked polymer (PIn-HCP) with high specific surface area was constructed via polyindole (PIn) as building blocks. Rich pore structures and abundant adsorption sites in PIn-HCP were obtained by hyper-cross-linking. The specific surface area of PIn-HCP was enhanced from 14.85 to 431.89 m2/g. The adsorption capacities of PIn-HCP-2 for methylene blue (MB), methyl orange (MO), rhodamine B (RhB), and tetracycline hydrochloride (TH) are 902.0, 275.2, 16.0, and 0.0 mg/g, respectively. PIn-HCP also realized selective adsorption of MB, which can better separate MB/RhB and MB/TH. MB is adsorbed onto PIn-HCP via a synergistic mechanism including π-π stacking, electrostatic interaction, cation-π interaction, hydrogen bonding interaction, and ion exchange. The huge conjugated structure of PIn promotes PIn-HCP to selectively adsorb MB. In addition, PIn-HCP also retains the electrochemical properties of PIn. MB can improve the specific capacitance of PIn-HCP up to five times, and it has potential as a supercapacitor electrode. PIn-HCP offers a promising and practical solution for the efficient treatment and utilization of organic pollutants in water.

في هذه الدراسة تم استخدام طريقة حيوية لتحضير جزيئات الفضة النانوية (AgNPs) من مستخلص فطر Metarhizium anisopliae. تم التعرف على خصائص AgNPs المحضرة باستخدام جهاز تحليل امتصاصية الطيف بالأشعة الضوئية والاشعة فوق البنفسجية، جهاز التحليل الطيفي بالأشعة تحت الحمراء. تم تحديد شكل وحجم وتوزيع الشحنات على جسيمات الفضة النانوية باستخدام المجهر الالكتروني الماسح وتحليل جهد زيتا. أظهر تحليل النشاط الحيوية لجسيمات الفضة النانوية فعاليتها في معالجة الملوثات بنسبة أكثر من 93 % من وزن نفط الخام في عينات المياه الملوثة. اذ تحولت كتلة النفط الخام في الماء بشكل فعال إلى كتلة هلامية فاقدة لقوامها واستحلابها، مقارنة بعينة النفط الخام (السيطرة)، بعد سبعة أيام من الحضانة عند درجة حرارة 28 ± 2 م°. تم إجراء التحليل الكيميائي لعينات المياه الملوثة بالنفط الخام المعالجة وغير المعالجة بالدقائق النانوية باستخدام تقنية كروماتوغرافيا الغاز- الكتلة (GC-MASS chromatography). أظهرت النتائج ظهور55 قمة بيانية (كل قمة بيانية تشير الى مركب كيميائي) في نموذج السيطرة بينما اختفت 51 قمة من هذه القمم واختزلت مساحة 4 قمم الأخرى. تم اختبار قدرة جسيمات الفضية النانوية في الحفاظ على فعاليتها في ظل ظروف التخزين المبردة لمدة ستة أشهر ومقارنتها بقدرة العزلة الفطرية قبل إنتاج جسيمات الفضة النانوية. أظهرت النتائج عدم وجود تغيرات معنوية في حجم وشكل وكفاءة جزيئات الفضة النانوية في معالجة الملوثات النفطية في الماء. اشارت النتائج إلى الكفاءة العالية لجسيمات الفضة النانوية مقارنة بالمواد الكيميائية في معالجة الملوثات البترولية وكذلك تعزيز قابلية الذوبان والاستحلاب وتفكك الهيدروكربونات. فضلاَ عن، تتميز جزيئات الفضة النانوية بكلف انتاج قليلة وتوفر مواد الانتاج رخيصة الثمن وسهولة وسرعة انتاجها وصديقة للبيئة مقارنة باستخدام المنتجات الكيميائية ذات سمية العالية للأحياء المائية وغالية الثمن وكلفة انتاجيتها العالية فضلاً عن تراكمها في النظام البيئي (غير امنة بيئيا).

Preparation of pompon-like ZnO-PANI heterostructure and its applications for the treatment of typical water pollutants under visible light

Layered double hydroxides (LDHs) are commonly used as adsorbents in the treatment of pollutants in water or air but with low adsorptive capacities. The LDH nanoflower lantern was fabricated using zeolitic imidazolate framework-67 (ZIF-67) nanocrystal as the template. The LDH nanoflower lantern has a hierarchically porous structure, with specific surface area of 214.28 m2 g–1 and pore diameters distributed in the range of 4.2–159.3 nm. Organic dyes in solution including Congo red (CR) and Rhodamine B (RhB) can be removed quickly, and the removal efficiencies approached 99.27% and 78.61%, respectively. The adsorption capacities of CR and RhB were determined to be 328.77 and 112.35 mg g–1. The as-prepared LDH nanoflower lantern showed high cyclic stability, can be fast regenerated in ethanol at 80 °C, and was considered promising for wide applications.

The rapid development of industry in recent years has led to the introduction of serious pollutants into water bodies, and there is an urgent need for efficient organic degradation technologies. At present, selective peroxynitrite (PS) oxidation (SR-AOPs) is an effective way to treat pollutants in water bodies, and it is necessary to select a suitable material for the activation of peroxynitrite. Metal-organic frameworks (MOFs), with their tunable structure, large specific surface area, and tunable ligand molecules exhibit excellent reactivity and catalytic performance in the activation of persulfate. With MOF-based materials for PS activation as a novel advanced oxidation technology, this study reviews MOFs and their composites and derived materials. The current research status of activated persulfate for the treatment of organic pollutants in water, the influence of different systems on the degradation performance are discussed, and the activation and degradation mechanisms are discussed; the problems of the above materials in the degradation of organic pollutants are summarized, and research directions based on the coupled activated persulfate system of MOF materials are proposed.

Detection and removal of trace amounts of toxic organic and inorganic pollutants in water and wastewater is important for the entire ecosystem. The development of new materials for the determination and removal of contaminants is constantly necessary. Layer double- hydroxides (LDHs) form a broad class of nanomaterials that represent anionic clay composite material used in research and development applications to protect the environment from pollutants. LDH structures functionalized with carbon-based materials are promising adsorbents in the extraction of organic and inorganic pollutants through adsorption and ion exchange mechanisms due to their increased versatility. This review describes recent studies on carbon-containing structure-based LDH composites used in the determination and removal of organic and inorganic pollutants in water and wastewater. Thus, it will lead to the realization of new studies for the determination and removal of different pollutants in other matrices besides water samples of LDHs.

With the significant economic shift, water pollution treatment has gradually become a key problem which needs to be deeply investigated for the sustainable development of China. In the face of specific water pollution incidents, multiple alternatives are often required to work together in order to achieve better results. However, due to the limitation of resources, alternatives must be ranked to realize the effective allocation of resources, which means the more highly ranked ones should possess more disposable resources. Furthermore, the water pollution treatment process is a multi-stage and multi-objective process. In each stage, decision-makers may have different emphasis and thus have different preferences for the treatment alternatives. How to effectively aggregate decision-makers' preferences in different stages into an overall preference so as to form a ranking of treatment alternatives under global constraints has turned into a problem worthy of discussion. Under such background, this paper proposes a multi-stage gray group decision-making method, where decision-makers use Group-G1 to rank and weight the criteria, and in this way, the weights of decision-makers and criteria in each stage could be determined. Considering the difference and deficiency of the cognitive level of decision-makers, this paper adopts the form of hesitant fuzzy linguistic term sets (HFITS) to express the evaluation information of decision-makers. And then, gray incidence analysis is selected to rank the alternatives. After ranking the alternatives in each stage, the multi-stage rankings will be aggregated into an overall ranking and the resource allocation is made according to the priorities of the alternatives. Finally, an example of water pollution treatment alternatives ranking based on a cyanobacterial bloom in Taihu Lake, China, is given to illustrate the proposed approach.

Research progress in the environmental application of magnesium hydroxide nanomaterials

Action and mechanism of semiconductor photocatalysis on degradation of organic pollutants in water treatment: A review

Complete mineralization of organic pollutants in water by treatment with air non-thermal plasma

To address the problem of petrochemical organic pollutants in water, specifically monoethylene glycol (MEG) present in industrial process streams, in this research, we synthesized and evaluated a multifunctional nanocomposite, Fe3O4@MC/MWCNT-CuO/Ag. The nanocomposite was produced by combining magnetic Fe3O4 nanoparticles, methylcellulose (MC), multi-walled carbon nanotubes (MWCNTs), and CuO/Ag nanoparticles by an integrated synthesis process. A consistent dispersion of nanoparticles, with diameters ranging from 30-40 nm, was discovered by FESEM analysis, showing effective integration without aggregation. Effective synthesis was demonstrated by well-doped and evenly dispersed CuO and Ag nanoparticles. Functional groups that improve electrostatic interactions with contaminants hence enhancing catalytic performance and adsorption efficiency, were validated by FTIR analysis. XRD indicated an unchanged crystal structure with an average crystallite size of 8.67 nm. The anticipated elemental composition was verified by EDS & mapping. A VSM study revealed magnetic characteristics (9.33 emu/g) that simplify nanocomposite separation and reuse. TGA proved thermal stability to be up to 600 °C. A BET study showed a highly specific surface area of 67.661 m2/g, enhancing adsorption. According to DRS and PL studies, the bandgap was lowered by 1.31 eV, which led to better optical absorption. The nanocomposite exhibited notable MEG removal efficiency, with 72 % in adsorption, 65 % in photocatalysis, and 56 % in sonocatalysis. This makes it a promising alternative for the remediation of organic pollutants in water treatment.