Field Of Environmental Engineering Research Articles

Effect of effuser throat diameter on the internal flow structure and energy characteristics of the jet pump

The jet pump is one of the most popular types of fluid machinery in agriculture, industry and environmental engineering and many other fields. However, its internal flow structure is complex, showing obvious unsteady characteristics. The effect of throat diameter size on jet pump performance and energy property was investigated in this study based on numerical calculation and test verification, in order to improve the performance and internal flow field stability of jet pump. Five models with different throat diameters were obtained by adjusting the assembly structure and simulated by the computational fluid dynamics software to solve the Navier–Stokes equations for three-dimensional steady flow. The accuracy of numerical methods was verified by comparison with the experimental results. The compact jet pump performance under different throat diameters was then compared and analysed. The backflow at effuser outlet of different throat diameters causes the changes of vortex structure inside the injector rear chamber. The vortex diffuses downstream to the impeller inlet, making the flow structure of the impeller inlet show obvious circumferential inhomogeneity. This forms different vortex structures at different impeller flow channels, changing the distribution of entropy production within the impeller, ultimately leading to a decrease of pump efficiency. Therefore, this study found that selecting a reasonable throat diameter of the injector can improve the performance of the jet pump impeller, and thus improve the overall efficiency of the system. For the research object in this paper, the recommended range of throat diameter of injector is 16 mm–17 mm. This finding could provide useful insights for the improvement of the hydraulic performance and operational stability of compact jet pumps.

Rehabilitation of the water supply network of Timişoara City from Timiş County in Romania

In such an urban centre like Timisoara (the largest one from the West of Romania), the problem of water treatment for drinking, respectively wastewater collection and treatment, have always been issues of strategic importance to the community. The policies of the European Union to support the financing of the member states in the field of environmental engineering and protection represented the basic pillar in the development of the water supply network also in this case. In light of the increasing and pressing need to efficiently manage scarce water resources, there has been renewed interest by water distribution network owners to develop and implement water management strategies and tools that would assist in the integrated and automated management of those networks. The modernizations made at the treatment plants can be summarized in a few basic ideas: the automatic control of processes, lower costs, and higher safety. The most commonly used rehabilitation techniques for reducing both types of water losses are pressure management and pipeline rehabilitation. In Timişoara City, this modernization, and the rehabilitation of the water supply network led to a significant reduction of the environmental pollution (water, soil, air), and to a better protection of human health. Investments in modern technologies for water treatment, which allow an automatic monitoring of the process, translate into more safety in exploitation, and, implicitly, a better-quality control. The main objectives pursued in this study aim at: improving the quality of drinking water supplied to the population, ensuring continuous supply of drinking water, compliance with the regulations in force, both Romanian and European, and ensuring the access for the majority of the population at this system. There were followed the rehabilitation systems for street drinking water supply networks, also those for street sewerage networks, with modern constructive solutions.

Overview of Polyethylene Based Multi-layered Geomembrane Through Blown Extrusion Process

Geomembranes are low-permeable liners used to control the molecular migration in many proven applications. Landfills is most common application in the field of civil and environmental engineering. Geomembrane is the main component in lining system which works as hydraulic barrier. The polyolefins are the basic materials of liner and more commonly polypropylene and polyethylene are preferred. Commercial manufacturing process involves extrusion techniques viz cast extrusion and blown extrusion process. The individual process is designed for multiple layered structures which are then coextruded to lead into a single liner. Typical structure comprises, high to low-density polyethylene (PE) resin, processing aids, stabilisers to retard the degradation through ultra-violet rays, photo-oxidation, and thermal oxidation. The stabilizer is usually used in smaller dosses to avoid degradations which includes, 2 to 3% carbon-black (CB), 0.5 to 1% antioxidants (AO), and plasticizing additives to introduce the flexibility. During the process, components are homogenised in specially designed screws of feeding and mixing zones. The formulated melt is co-extruded through specially designed die of multi-layered structures. The subsequent melt enters in circular die with a certain pressure which leads to bubbled shaped films. The variation in the surface morphology layer structure and layer number are the important technical aspects to alter the required end application. Finally, manufactured geomembrane is qualified as per the international specifications which are governed by geosynthetic research institute (GSI/GRI).

The challenges of Process Engineering for the reuse of treated wastewater within INRAE’s REUSE network - the need for a multidisciplinary and multi-scale approach

The reuse of wastewater aims to mobilize and treat, for certain uses and under certain conditions, water that has already been used. Rather than discharging wastewater into the natural environment, this practice aims to recover it by replacing the mobilization of water withdrawn from the environment [van Loosdrecht and Brdjanovic, 2014]. By moving from a linear logic of the mobilization and use of water to a circular approach, the objective pursued is to reduce the pressure, qualitative then quantitative, on the resources while limiting, as far as possible, the usage conflicts. It is in fact a question of passing from a simple competitive mode which strongly mobilizes resources, to a complex mode, known as “circular”, of putting in complementarity of uses. This approach initially mainly concerned agricultural uses insofar as agricultural needs represent the majority of the water mobilized, including developed countries [UN Water 2018]. Cities integrate specific issues that are characterized by significantly different options from those that can be found in rural areas. In the city, the recovery of wastewater has both material aspects (water, nutrients, critical metals, biopolymers, etc.) and energy aspects (recovery of heat from the networks, production of energy by biological means and /or thermal,…) which should be integrated on an appropriate scale according to the problems addressed (housing, building, district, city, territory or hydrological basin). To study the conditions under which REUSE can develop and be implemented in a safe and sustainable manner, research is needed [Ait-Mouheb et al., 2018]. If it represents an opportunity in certain territories where wastewater can be mobilized, it is also necessary to underline the limits of this practice in territories where the wastewater discharged into the environment is necessary to maintain the low water levels of rivers and rivers, or where soils may be affected, for example, by the salinity of these waters. In addition, studies of the social, economic and environmental dimensions differ significantly depending on the uses envisaged and the situations considered. To meet these challenges, the REUSE network of INRAE (cf. www6.inrae.fr) proposes to adopt a multidisciplinary and multi-scale approach by mobilizing not only the disciplines that can be considered as falling within the field of technologies and environmental engineering but also all of those relating to the human and social sciences, economics, legal, and participatory sciences.

International Conference on Civil and Environmental Engineering 2022 (CENVIRON2022) Special Issue on Sustainable Environment & Communities August 29-30, 2022 · Penang, Malaysia

Editors Ayu Wazira Azhari, Naimah Ibrahim, Fahmi Muhammad Ridwan, Razi Ahmad, Norazian Mohamed Noor, Ho Li Ngee, Farrah Aini Dahalan, Ilya Joohari, Shamilah Anudai & Zulkarnain Hassan. Organiser Center of Excellence, Water Research and Environmental Sustainability Growth (WAREG), Universiti Malaysia Perlis, Perlis, MalaysiaFaculty of Civil Engineering & Technology, Universiti Malaysia Perlis, Perlis, MalaysiaSchool of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China Preface The International Conference on Civil and Environmental Engineering 2022 (CENVIRON2022) - Special Issue on Sustainable Environment & Communities took place on 29 – 30 August 2022 at Penang, Malaysia. The conference was jointly organized by the Center of Excellence, Water Research and Environmental Sustainability Growth (WAREG), Universiti Malaysia Perlis, the Faculty of Civil Engineering & Technology, Universiti Malaysia Perlis and School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China.This conference brought together researchers, practitioners, engineers and students worldwide in hope to extend networking, integrate knowledge and exchange ideas among participants. This year, the theme “Towards safe, resilient and sustainable cities for humankind” takes an in-depth look at cutting edge research and development that address major topics in various environmental sustainability-related research. Over 70 distinguish researchers, practitioners, engineers and students from across the country have presented their current and intriguing research in the scope of civil and environmental engineering and technology, which evolved around six major areas: water protection, water resources and hydrology, technologies for water management, energy and water, air and noise and sustainable materials.The conference has gained tremendous success due to collective efforts from the organizing committees, the co-organizers, the reviewers, presenters, and all participants. Special acknowledgment goes to the keynote speakers who assent our invitation and successfully delivered interesting talks to catch all the participants’ attention. The keynote speeches were delivered by Professor Dr. Kun Guo from the School of Chemical Engineering and Technology, Xi’an Jiaotong University China with the topic “Microbial electrochemical technology for energy and resource recovery from wastewater” and Professor Ar. Dr. Abdul Razak Sapian from the Kullliyyah of Architecture and Environmental Design, International Islamic University Malaysia (IIUM), Malaysia with the topic “Madani Built Environment”We would like to thank all the reviewers involved in ensuring each contributed paper were refereed and accepted based on interests, relevance, innovation and pure contribution towards the civil and environmental engineering and technology fields. Acknowledgement and gratitude also goes to Astasoft Sdn. Bhd. and Mega Jati Academy for sponsoring this conference. Finally special thanks goes to the Universiti Malaysia Perlis for the continuous support throughout the conference event. Che Zulzikrami Azner Abidin Chairman,International Conference on Civil and Environmental Engineering 2022 (CENVIRON2022)Special Issue on Sustainable Environment & CommunitiesList of Committee is available in this pdf.

Machine Learning for Water Quality Assessment Based on Macrophyte Presence

The ecological state of the Danube River, as the world’s most international river basin, will always be the focus of scientists in the field of ecology and environmental engineering. The concentration of orthophosphate anions in the river is one of the main indicators of the ecological state, i.e., water quality and level of eutrophication. The sedentary nature and ability to survive in river sections, combined with the presence of high levels of orthophosphate anions, make macrophytes an appropriate biological parameter for in situ prediction of in-river monitoring processes. However, a preliminary literature review identified a lack of comprehensive analysis that can enable the prediction of the ecological state of rivers using biological parameters as the input to machine learning (ML) techniques. This work focuses on comparing eight state-of-the-art ML classification models developed for this task. The data were collected at 68 sampling sites on both river sides. The predictive models use macrophyte presence scores as input variables, and classes of the ecological state of the Danube River based on orthophosphate anions, converted into a binary scale, as outputs. The results of the predictive model comparisons show that support vector machines and tree-based models provided the best prediction capabilities. They are also a low-cost and sustainable solution to assess the ecological state of the rivers.

Functionalized β-cyclodextrin with polyethyleneimine-coated Fe3O4 as a recyclable demulsifier for the efficient treatment of oily wastewater

The treatment of oily wastewater is an urgent problem in the environmental engineering fields. In view of the problems of secondary pollution and difficult recycling of existing demulsifier, a magnetic nanometer demulsifier Fe3O4 @PEI@ β-CD with high interfacial activity was synthesized. The chemical composition, structure, morphology and magnetic properties of Fe3O4 @PEI@ β-CD were characterized by FTIR, XRD, TEM, DLS and VSM. In addition, the effects of dosage, temperature, settling time and pH value on demulsification performance were detailly studied. The results showed that Fe3O4 @PEI@ β-CD can realize separation of oil from oily wastewater quickly and efficiently in a wide pH range at room temperature. And under acidic, neutral and alkaline conditions, the demulsification efficiency was more than 95 % when the dosage of Fe3O4 @PEI@ β-CD was 200 mg /L, the temperature was 45 ℃, and the settling time was 30 min. In the recyclability test, the demulsification efficiency did not decrease significantly after 11 times of recycling. Furthermore, the mechanism of demulsification was investigated through interfacial tension, zeta potential and optical microscopy. The finding suggests that Fe3O4 @PEI@ β-CD is an efficient, recyclable and environmentally friendly demulsifier that is expected to be used for oil-water separation.

New outlook on hazardous pollutants in the wastewater environment: Occurrence, risk assessment and elimination by electrodeionization technologies

Over the decades, water contamination has increased substantially and has become a severe global issue. Degradation of natural resources is taking place at an alarming rate as a result of the use of chemicals like dyes, heavy metals, fertilizers, pesticides, and many more, necessitating the development of long-term pollution remediation methods/technologies. As a new development in the field of environmental engineering, electrodeionization incorporates both traditional ion exchange and electrodialysis. This communication provides an overview of hazardous contaminants such as dyes, heavy metals, fertilizers, and pesticides, as well as their converted forms, which are present in water. It highlights the risks of water pollutants to public health and the environment. Various electrochemical methods with a focus on electrodeionization for the treatment of wastewater and removal of hazardous contaminants are outlined in this review. Additionally, this review discusses the challenges and the future outlook for the development in this field of research.

Nanovesicle and extracellular polymeric substance synthesis from the remediation of heavy metal ions from soil

Heavy metal toxicity affects aquatic plants and animals, disturbing biodiversity and ecological balance causing bioaccumulation of heavy metals. Industrialization and urbanization are inevitable in modern-day life, and control and detoxification methods need to be accorded to meet the hazardous environment. Microorganisms and plants have been widely used in the bioremediation of heavy metals. Sporosarcina pasteurii, a gram-positive bacterium that is widely known for its calcite precipitation property in bio-cementing applications has been explored in the study for its metal tolerance ability for the first time. S. pasteurii SRMNP1 (KF214757) can tolerate silver stress to form nanoparticles and can remediate multiple heavy metals to promote the growth of various plants. This astounding property of the isolate warranted extensive examinations to comprehend the physiological changes during an external heavy metal stress condition. The present study aimed to understand various physiological responses occurring in S. pasteuriiSRMNP1 during the metal tolerance phenomenon using electron microscopy. The isolate was subjected to heavy metal stress, and a transmission electron microscope examination was used to analyze the physiological changes in bacteria to evade the metal stress. S. pasteurii SRMNP1 was tolerant against a wide range of heavy metal ions and can withstand a broad pH range (5–9). Transmission Electron Microscopy (TEM) examination of S. pasteurii SRMNP1 followed by 5 mM nickel sulfate treatment revealed the presence of nanovesicles encapsulating nanosized particles in intra and extracellular spaces. This suggests that the bacteria evade the metal stress by converting the metal ions into nanosized particles and encapsulating them within nanovesicles to efflux them through the vesicle budding mechanism. Moreover, the TEM images revealed an excessive secretion of extracellular polymeric substances by the strain to discharge the metal particles outside the bacterial system. S. pasteurii can be foreseen as an effective bioremediation agent with the potential to produce nanosized particles, nanovesicles, and extracellular polymeric substances. This study provides physiological evidence that, besides calcium precipitation applications, S. pasteurii can further be explored for its multidimensional roles in the fields of drug delivery and environmental engineering.

Phytoremediation, Bioaugmentation, and the Plant Microbiome.

Understanding plant biology and related microbial ecology as a means to phytoremediate soil and groundwater contamination has broadened and advanced the field of environmental engineering and science over the past 30 years. Using plants to transform and degrade xenobiotic organic pollutants delivers new methods for environmental restoration. Manipulations of the plant microbiome through bioaugmentation, endophytes, adding various growth factors, genetic modification, and/or selecting the microbial community via insertion of probiotics or phages for gene transfer are future areas of research to further expand this green, cost-effective, aesthetically pleasing technology─phytoremediation.

Performance of integral polypropylene packing coated with polydimethylsiloxane in biotrickling filter for toluene elimination

Biotrickling filters (BTFs) for volatile organic compounds (VOCs) have attracted tremendous research attention in the field of environmental engineering. However, the problem of clogging occurred during the long-term operation limits their practical applications. To alleviate the clogging, an integral polypropylene (PP) packing coated with polydimethylsiloxane (PDMS) was prepared, and in combination with fungus, its performance was investigated for toluene elimination. Two laboratory-scale BTFs were started at low toluene concentrations of 200–900 mg·m−3. Subsequently, a series of experiments were conducted at toluene concentrations of 47–2906 mg·m−3, with empty bed residence time (EBRT) values of 50 and 40 s. Toluene removal efficiency reached 100 % at the inlet toluene concentration of 296–560 mg∙m−3 for EBRT of 50 s. The maximum elimination capacity (EC) of 98 g∙m−3∙h−1 was obtained at an inlet toluene load of 117.67 g∙m−3∙h−1. Clogging was relieved by manual cleanup, and the BTFs were operated steadily for nearly 8 months. CO2 production was monitored during the whole operation, and toluene mineralization was evaluated simultaneously. Furthermore, the biofilm structure and microbial diversity were analyzed.

Magnetic Technologies and Green Solvents in Extraction and Separation of Bioactive Molecules Together with Biochemical Objects: Current Opportunities and Challenges

Currently, magnetic technology and green solvents are widely used in chemical engineering, environmental engineering and other fields as they are environmentally friendly, easy to operate and highly efficient. Moreover, a magnetic field has positive effect on many physicochemical processes. However, related new methods, materials, strategies and applications in separation science still need to be developed. In this review, a series of meaningful explorations of magnetic technologies for the separation of natural products and biologic objects, including magnetic ionic liquids and other magnetic solvents and fluids, magnetic nanoparticles and magnetic fields, and the development of magnetic separators were reviewed. Furthermore, the difficulties in the application and development of magnetic separation technology were discussed on the basis of comparison and data analysis, especially for the selection of magnetic materials and magnetic field sources. Finally, the progress in the development of magnetic separators was also elaborated for researchers, mainly including that of the new high-efficiency magnetic separator through multi-technology integration and the optimization of traditional magnetic separators, which help current techniques break through their bottleneck as a powerful driving force.

AWWA Water Science Author Spotlight

Having published an article in AWWA Water Science, Leigh Terry answered questions from the publication's editor-in-chief, Kenneth L. Mercer, about the research. Evaluation of the Biodegradability of Fluorescent Dissolved Organic Matter via Biological Filtration Melanie Vines and Leigh G. Terry Leigh at the Universidad del Norte (Barranquilla, Colombia), completing her Fulbright Specialist Program. A hot summer day in Guatemala piqued my interest in water research and set me on the career path I am on today. I traveled to Guatemala in the summer between my sophomore and junior year of college through Athletes in Action. My team and I had finished running 12 miles on the track in Guatemala City, and water was the first thing we wanted. Much to our dismay, the bottled water we brought was inadequate to quench our thirst. Unable to refill our bottles from the faucet, I began to wonder what was in the tap water that would make us sick and how we could remove it. I researched career paths that would allow me to continue to ask these questions and found the field of environmental engineering. I love asking questions and seeking the answers. Being a long-distance runner, I have developed endurance and persistence to finish what I start (which can often be an issue in the lab!) and I think these traits will help me succeed as a researcher. Ask questions, seek answers, and do not give up when it gets hard or you can't quite see the finish line. Leigh and her family hiking at the University of Alabama Arboretum in Tuscaloosa. Leigh (white hat) and her research group at a monthly pub run. Nature and people have always fascinated me. I love living in community with others, and I try to be cognizant of my environmental impact. I see these two themes intersect in my research as I focus on sustainable technologies to solve fundamental water treatment problems to improve a community's quality of life. I also love to travel, so I incorporate international components into my research. For example, I completed a Fulbright Specialist Program in Colombia last year, and I co-lead a study-abroad program in Italy in the summers. Leigh (first row, right) with students and professors from the University of Alabama, Tuskegee University (Ala.), and Universidad del Norte, visiting a water treatment plant that employs membrane filtration. The goal is to help utilities optimize organic carbon removal in drinking water to meet regulations (organic carbon, disinfection byproducts, regrowth, etc.) to protect public health. Utilities will need to diversify source water as typical source waters become scarce; thus, our research can provide insights into different types of source waters and the fractions of DOM removed in each via biological filtration. I grew up in Alabama and went to graduate school in Colorado. Alabama is considered a “water-rich” state and America's Amazon because of the biodiversity of the river network and surrounding forests. I grew up water skiing and swimming in the Tombigbee River and traveling to the Gulf Coast to visit the beaches. I always appreciated the water (especially in Alabama's hot summers), but I never realized its scarcity until I moved to Colorado for graduate school. Water security is an issue that affects every state, and policies to protect our water resources are needed for future generations. As traditional source waters become scarce and/or more contaminated, utilities are forced to look into alternative sources and creative treatment technologies to meet these new challenges. I love running and the gift of being outside, so I schedule runs into my weekly calendar. My research team participates in our local monthly pub run around town to make sure we are all taking time away the lab and enjoying one another's company in the open air. I also love hiking or swimming with my family. We have small kids, so I try to spend as much time outside with them as possible. While Leigh is an author of the article featured here, she is also a recent addition to AWWA Water Science's editorial board. To learn more about Leigh's research, visit the article, available online at https://doi.org/10.1002/aws2.1201. AWWA members have access to this and all AWWA Water Science research articles for free. Learn more about AWWA's digital, peer-reviewed journal by visiting www.awwawaterscience.com.

Immobilization of Biomass Materials for Removal of Refractory Organic Pollutants from Wastewater.

In the field of environmental science and engineering, microorganisms, enzymes and algae are promising biomass materials that can effectively degrade pollutants. However, problems such as poor environmental adaptability, recycling difficulties, and secondary pollution exist in the practical application of non-immobilized biomass materials. Biomass immobilization is a novel environmental remediation technology that can effectively solve these problems. Compared with non-immobilized biomass, immobilized biomass materials have the advantages of reusability and stability in terms of pH, temperature, handling, and storage. Many researchers have studied immobilization technology (i.e., methods, carriers, and biomass types) and its applications for removing refractory organic pollutants. Based on this, this paper reviews biomass immobilization technology, outlines the mechanisms and factors affecting the removal of refractory organic pollutants, and introduces the application of immobilized biomass materials as fillers for reactors in water purification. This review provides some practical references for the preparation and application of immobilized biomass materials and promotes further research and development to expand the application range of this material for water purification.

Influence of stress-level due to self-weight on the hydraulic conductivity of permeable concrete for geotechnical applications

Permeable concrete is effectively used in many fields of civil and environmental engineering, including some geotechnical applications such as drainage piles, deep drainage trenches, and as a permeable backfill material for retaining walls. The principal requirements that a pervious concrete must have for geotechnical applications are those that simultaneously guarantee enough hydraulic conductivity and good filter properties against internal erosion of the soil in which the drains are realised. These requirements can be effectively achieved through special mix-designs in which a non-negligible amount of sand is added to the aggregates, unlike the permeable concretes used for example in the road construction sector where the aggregates are essentially made only of gravel and the concrete is a “no-fines” concrete. The permeability of the pervious concrete depends on many factors among which the stress level due to the self weight of the column of fresh concrete when the depth of the same column is non negligible, as it is in the geotechnical applications. Results of an experimental study on this aspect are reported in the paper. These results show that the hydraulic conductivity reduced with the vertical stress level due to the self weight of the fresh permeable concrete. This reduction is very significant in the range of vertical stress σv of 1–100 kPa (that correspond to the self-weight of a column of “classical” fresh pervious concrete h* ranging from about 0.1 to 6 m). Subsequently this reduction is less marked up to the maximum stress level reached in the tests (σv=700kPa, h* about 40 m). The minimum hydraulic conductivity (hydraulic conductivity for σv=700kPa) is, however, still sufficient and adequate for draining medium to fine-grained base soils (soil near piles or trench drains) such as clays, silty-clays, sandy-silts, silty-sands, and fine sands.

Adsorption of phenol by sugarcane biochar@bentonite

Phenol is a hazardous organic chemical that is introduced into the environment by industrial and pharmaceutical discharges. Bentonite can remove harmful substances in the environment and is widely used in the field of environmental geotechnical engineering. However, the adsorption effect of bentonite on organic pollutants is poor. At the same time, its permeability and expansion characteristics are easily affected by saline solutions and acid aqueous solutions. Biochar, as a simple and low-cost adsorbent, can effectively remove inorganic and organic pollutants. The purpose of this study is to prepare a composite material including biochar and bentonite and improve the removal efficiency of phenol and the impermeability of bentonite in saline and acidic aqueous solutions. The adsorbents were characterised by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller nitrogen (N2) method. The permeability coefficients of bentonite and sugarcane biochar@bentonite (SuBC@Ben) were determined. The effects of bentonite, SuBC@Ben and sugarcane biochar on the removal of phenol under different contact times, concentrations, pH values and temperatures were studied. The results show that the change range of the SuBC@Ben permeability coefficient is not obvious with the increase in saline solution concentration, indicating that SuBC@Ben has good impermeability in saline solution.

Reactive transport in membrane separation modeling: A perspective

Reactive transport modeling refers to the coupling of chemical equilibrium reactions with rate-dependent phenomena such as transport and phase change. The concept originated and is widely used in geosciences but has been infiltrating other fields. Reactive transport can contribute to model prediction and fundamental understanding of transport phenomena by illuminating the interrelations between species distribution of solutes and their displacement. Despite many potential benefits, the Chemical Environmental Engineering field has been slow at adopting the reactive transport approach. Here we focus on reactive transport modeling of membrane separation processes in aqueous solutions for environmental applications. We briefly review the progress made in the last decades for selected technologies and discuss the potential in further developing reactive transport modeling for each case. We then discuss several common misunderstandings and knowledge gaps while highlighting the challenges and opportunities of implementing the reactive transport approach in membrane transport modeling and simulation.

Imprinted polymer beads featuring both predefined multiple-point interaction and accessible binding sites for precise recognition of 2′-deoxyadenosine

“Tailor-made” formation of complementary binding sites via lock-and-key molecular binding mechanism is critical for selective adsorption of target molecules in environmental and chemical engineering fields. However, the innovative design of molecularly imprinted polymers (MIPs) remains a challenging task. Here, photo-crosslinked functional polymer building blocks consisting of monomeric methacrylic acid (MAA), 1-(vinylbenzyl)thymidine (VBT) and post-crosslinked monomeric cinnamoyloxyethyl methacrylate (CEMA) were firstly synthesized. MIPs beads (PC-MIPs) were then prepared by emulsion droplet microreactor, and finally their precise recognition of 2'-deoxyadenosine (dA) was investigated by batch mode adsorption. The prepared PC-MIPs microspheres have a large number of voids on the surface with interconnected cavities inside, and the bubble-like framework inside may be caused by the full encapsulation of bubbles from the low boiling point isolated phase. Due to the high density of accessible imprinted sites and strong interaction with dA, the maximum monolayer adsorption capacity of PC-MIPs was calculated to be 134.5 μmol g−1 for dA, surpassing most of the reported dA-imprinted sorbents. In addition, unique advantages of the post-crosslinking strategy combined with the emulsion template method exhibited good selectivity (imprinting factor higher than 2.71) and high stability, as well as excellent recyclability toward dA. Moreover, 82.4 % of dA was extracted by PC-MIPs from spiked human urine samples. Therefore, our work demonstrated an alternate strategy to design polymers bearing precise molecular recognition capability, and provided a new perspective for dA enrichment from biological samples.

Nitrogen Dioxide Detection in Hollow Core Fiber With Long Dynamic Range

We present a compact nitrogen dioxide (NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) detection system using a wavelength-tunable single-frequency blue laser in hollow core fiber with absorption dips and photoacoustic (PA) signals. The molecular NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> has a harmful impact on human health, such as lung function and visibility decreasing. It even inhibits plant growth. How to detect NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> with low detection limit and long dynamic range is a vital issue. However, an ultralow detection limit sometimes means these devices cannot work well under high concentration level. Compared with ultralow detection limits, long dynamic range was considered more important for the fields of agricultural and environmental engineering. So, we combined two detection methods in one optomechanical design: PA and direct absorption spectroscopies. The interaction between the NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> molecules and lights in hollow core fiber can be effectively increased. High light absorption induced fast heating process. The ppb detection limit can be realized by the PA signals. But due to the mechanic design, the nonlinearity of PA signals can be found at high concentration level. Compared with PA, the direct absorption spectroscopy can be extended to high concentration level. Long dynamic range, i.e., 57 dB, can be achieved with this one optomechanical design. The ppb detection limit of PA signals can also be realized. The work range for NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> concentration can be from 2 ppb to 1000 ppm. The long-term instability was estimated as 0.11%.

Designing of 3D MnO2-graphene catalyst on sponge for abatement temperature removal of formaldehyde

The Mn-based catalysts, with low cost and high activity, are believed to be the effective composites for eliminating in-door formaldehyde (HCHO), while the powdered form nanosized catalysts are hardly to apply for practical application. Herein, hetero-structure of nanosheets manganese oxide (MnO2) encapsulating N-doping graphene sphere (GS) were deposited in network-like sponge for constructing 3D catalyst. The prepared MnO2-GS-Sponge composite catalyst exhibited excellent performance for removing HCHO at room temperature compared with GS and commercial MnO2. The MnO2-GS with larger specific surface area (209.1 m2·g−1) was dispersed evenly in 3D network of sponge, which facilitated exposing more activate sites and achieving fast transport kinetics accelerating catalytic reaction for converting 97.1 % of 100 ppm of HCHO continuously to CO2 for 120 h. Moreover, rely on the chemisorption of amino groups on N-doping GS surface, HCHO could be enriched even at low concentrations and efficient elimination (from 1000 ppb to12 ppb, at 35 ℃ in 48 h). The average oxidation state and infrared spectra analysis suggested that abundant oxygen vacancies on MnO2-GS-Sponge could be identified as surface-active sites of converting HCHO into the intermediates of dioxymethylene and formate. This work might inspire the designing 3D composite material for potential application in other fields of environmental engineering or energy industrial.