Water Treatment Chemicals Research Articles

Using Artificial Neural Networks to Predict Operational Parameters of a Drinking Water Treatment Plant (DWTP)

The scope of the present study is the estimation of key operational parameters of a drinking water treatment plant (DWTP), particularly the dosages of treatment chemicals, using artificial neural networks (ANNs) based on measurable in situ data. The case study consists of the Aposelemis DWTP, where the plant operator had an estimation of the ANN output parameters for the required dosages of water treatment chemicals based on observed water quality and other operational parameters at the time. The estimated DWTP main operational parameters included residual ozone (O3) and dosages of the chemicals used: anionic polyelectrolyte (ANPE), poly-aluminum chloride hydroxide sulfate (PACl), and chlorine gas (Cl2(g)). Daily measurable results of water sample analysis and recordings from the DWTP Supervisory Control and Data Acquisition System (SCADA), covering a period of 38 months, were used as input parameters for the artificial neural network (1188 values for each of the 14 measurable parameters). These input parameters included: raw water supply (Q), raw water turbidity (T1), treated water turbidity (T2), treated water residual free chlorine (Cl2), treated water concentration of residual aluminum (Al), filtration bed inlet water turbidity (T3), daily difference in water height in reservoir (∆H), raw water pH (pH1), treated water pH (pH2), and daily consumption of DWTP electricity (El). Output/target parameters were: residual O3 after ozonation (O3), anionic polyelectrolyte (ANPE), poly-aluminum chloride hydroxide sulfate (PACl), and chlorine gas supply (Cl2(g)). A total of 304 different ANN models were tested, based on the best test performance (tperf) indicator. The one with the optimum performance indicator was selected. The scenario finally chosen was the one with 100 neural networks, 100 nodes, 42 hidden nodes, 10 inputs, and 4 outputs. This ANN model achieved excellent simulation results based on the best testing performance indicator, which suggests that ANNs are potentially useful tools for the prediction of a DWTP’s main operational parameters. Further research could explore the prediction of water chemicals used in a DWTP by using ANNs with a smaller number of operational parameters to ensure greater flexibility, without prohibitively reducing the reliability of the prediction model. This could prove useful in cases with a much higher sample size, given the data-demanding nature of ANNs.

Ferrate(VI) green oxidant: electrochemical generation, self‐decomposition, and application for reactive red 195 azo dye treatment

AbstractBACKGROUNDFerrate(VI), an environmentally friendly oxidant, has recently emerged as one of the most promising chemicals for water and wastewater treatment due to its versatile application as an oxidant, coagulant, and disinfectant. In this paper, the factors affecting the electrosynthesis process of ferrate using ductile iron anode were studied. Besides, the obtained ferrate was used to remove reactive red 195 (RR195).RESULTSThe optimal ferrate electrochemical synthesis conditions were determined, including 14 mol L−1 NaOH electrolyte solution, a current density of 40 mA cm−2, and electrolysis time of approximately 5–6 h. Furthermore, the kinetics of the ferrate's self‐decomposition reaction was also studied at different temperatures. The decomposition process of ferrate in a 14 mol L−1 NaOH environment followed second‐order kinetics, with reaction rate constants of 4.70 × 10−9, 7.31 × 10−8, 1.95 × 10−7, and 4.70 × 10−7 (L mol−1 s−1) at temperatures of 4, 10, 20, and 30 °C, respectively. RR195 treatment efficiency by ferrate reached 96.3% in a short time of 3 min at pH 3 with a ferrate/RR195 molar ratio of 30/1.CONCLUSIONThis study identified the optimal conditions for the electrochemical synthesis of ferrate using a ductile iron anode. Ferrate was stable at a low temperature of 4 °C, so unused ferrate needs to be stored at low temperatures to avoid decomposition of ferrate. The ferrate green oxidant demonstrated high efficiency in the treatment of RR195 in a short time. © 2024 Society of Chemical Industry (SCI).

Optimasi Injeksi Trisodium Phosphate Pada Air Suplai Boiler Di Unit 4 PLTU Nagan Raya Menggunakan Design Expert Metode Pendekatan Response Surface Bok-Behnken

In the steam power plant industry, supporting facilities commonly called BOP (Balance of Plant) include Coal Handling, Ash Handling and WTP (Water Treatment Plant). TSP Trisodium Phosphate is one of the chemicals in water treatment. Besides functioning as a cleaner, TSP also functions to precipitate magnesium, iron, and silica and is able to help maintain the pH value of boiler water. Therefore, this activity was carried out to optimise chemical injection in the water treatment process for boiler water with good quality so as to produce steam with good quality as well. From the analysis results, the optimum injection of chemicals is 0.462 ppm TSP (Trisodium Phosphate) resulting in a pH value of 9.279, SiO2 (Sillicon dioxyde) 64.5 ppb, and Na+ (Sodium) 0.719 ppb.

Influences of Heavy Metals in Water Treatment Chemicals on Drinking Water Quality and Risk Management

Water treatment chemicals (WTCs) are important raw materials during the drinking water production process. Occasionally unqualified WTCs with heavy metals were provided to Water Treatment Plant（WTP） by supplier during emergency situation，such as earthquake, typhoon and city block for epidemic disease, just because it cannot obtain the qualified WTCs. The harmful heavy metals in WTCs may expose a certain health risk to the quality of drinking water. In this paper, the influence of heavy metals in WTCs on the quality of drinking water was explored and the feasible management measures are proposed, taking the ILha Verda Water Plant (IVP) in Macao as an example. The study was based on the testing results of heavy metals in WTCs and treated water from 2017 to 2022 in IVP. A series of mathematical models were established to evaluate the content of heavy metals in water brought by WTCs. The removal rates of the water treatment process to the heavy metals were calculated at same time. The maximum allowable concentrations of heavy metals in WTCs were calculated and accessed. The results show that the drinking water is safety if the heavy metals in unqualified WTCs are under the maximum allowable concentrations. Then it is proposed for the classification of WTCs and risk management. The study will provide theoretical and technical support for water quality safety supervision and water supply management.

Field and laboratory studies of fluorescence-based technologies for real-time tracking of cyanobacterial cell lysis and potential microcystins release

Elevated levels of dissolved microcystins (MCs) in source water due to rapid cell lysis of harmful cyanobacterial blooms may pose serious challenges for drinking water treatment. Catastrophic cell lysis can result from outbreaks of naturally-occurring cyanophages – as documented in Lake Erie during the Toledo water crisis of 2014 and in 2019, or through the application of algaecides or water treatment chemicals. Real-time detection of cyanobacterial cell lysis in source water would provide a valuable tool for drinking water plant and reservoir managers. In this study we explored two real-time fluorescence-based devices, PhycoSens and PhycoLA, that can detect unbound phycocyanin (uPC) as a potential indication of cell lysis and MCs release. The PhycoSens was deployed at the Low Service pump station of the City of Toledo Lake Erie drinking water treatment plant from July 15 to October 19, 2022 during the annual cyanobacteria bloom season. It measured major algal groups and uPC in incoming lake water at 15-min intervals during cyanobacteria dominant and senescence periods. Intermittent uPC detections from the PhycoSens over a three-month period coincided with periods of increasing proportions of extracellular MCs relative to total (intracellular and extracellular) MCs, indicating potential for uPC use as an indicator of cyanobacterial cell integrity. Following exposures of laboratory-cultured MCs-producing Microcystis aeruginosa NIES-298 (120 μg chlorophyll/L) to cyanophage Ma-LMM01, copper sulfate (0.5 and 1 mg Cu/L), sodium carbonate peroxyhydrate (PAK® 27, 6.7 and 10 mg H2O2/L), and potassium permanganate (2.5 and 4 mg/L), appearance of uPC coincided with elevated fractions of extracellular MCs. The PhycoLA was used to monitor batch samples collected daily from Lake Erie water exposed to algaecides in the laboratory. Concurrence of uPC signal and surge of dissolved MCs was observed following 24-h exposures to copper sulfate and PAK 27. Overall results indicate the appearance of uPC is a useful indicator of the onset of cyanobacterial cell lysis and the release of MCs when MCs are present.

Manganese Detection and Removal from Surface Water: A case study from Mengkubau Water Treatment Plant

The study of water contamination, especially in developing countries, has become more crucial in recent years as the demand for clean, drinkable water has increased. Brunei Darussalam’s primary water supply comes from surface waters, and each year, BND $ 9 to 10 million is spent on chemicals for water treatment. Recently, the Mengkubau dam, which supplies water to the Brunei Muara District, has been upgraded in terms of its height to meet the increased demand. Because of this, the amount of manganese in raw water went up, especially during the rainy season. This caused problems for the Mengkubau Water Treatment Plant (MWTP). So, a study was done to find out where the extra manganese was coming from and how it could be stopped to help solve the problems in a more cost-effective and long-term way. Rock samples from the dam and rainfall data, as well as the data for manganese concentration in the raw water, were collected to understand the source of manganese. The results showed that the rocks contributed to the manganese concentration in the raw water, which increased by almost nine folds. Furthermore, rainfall influences manganese concentration because concentration is higher in the rainy season compared to the dry season. Also, an experiment was done to see if water lettuce, or Pistia stratiotes, could be used as a sustainable and cost-effective treatment. The efficiency of manganese removal through water lettuce varies depending on the exposed weather condition. The highest removal efficiency of 97% was achieved when the water lettuce was placed in the shade.

Import Substitution of Chemicals for Water Treatment at Series-Configuration Combined-Cycle Units

Import Substitution of Chemicals for Water Treatment at Series-Configuration Combined-Cycle Units

Effect of three commonly used aquaculture chemicals against enteropathogenic Escherichia coli and Salmonella spp.

Enteric bacteria such as Escherichia coli and Salmonella spp. are significant fish pathogens and related to thousands of cases of food-borne diseases every year in human. Since aquatic environments are reservoirs of these pathogens, they may contaminate the food fish and result in outbreaks. Therefore, it is crucial to reduce or eliminate these pathogens from aquaculture facilities. We tested effectiveness of three commonly used aquaculture chemicals, viz., lime, hydrogen peroxide and zeolite on bacterial load, Escherichia coli and Salmonella spp. under laboratory and earthen pond conditions where they were applied at a dose recommended for freshwater aquaculture. Results of the bacteriological study showed that lime had a significant role in reducing bacterial abundance from an initial value of 1.5 × 103 to 1.9 × 103 cfu/ml and 3.9 × 103 to 6.3 × 103 to a final value of 1.2 × 103 to 1.5 × 103 cfu/ml and 1.9 × 103 to 6.3 × 103 cfu/ml within 24 h under aquaria and pond condition, respectively. A complete inactivation of E. coli was observed in lime treated aquaria and ponds 24 h post-treatment, whereas Salmonella spp. remained unaffected in pond water but inactivated under aquarium condition after same period. However, neither hydrogen peroxide nor zeolite treatment reduced total bacterial count as well as E. coli and Salmonella even after 1-week post-treatment. It is, therefore, recommended that the water treatment chemicals should be applied in aquaculture ponds at appropriate dose, and farmers need to adopt biosecurity measures to ensure food safety.

Supply Chain Threats Persist

Since early 2020, critical infrastructure sectors have endured myriad conditions that have threatened their continuity of operations. Most business entities are not autonomous or self-sufficient; rather they depend on a complex and often global supply chain of essential goods and services—this is certainly true of drinking water and wastewater systems. Supply chain matters were a roller coaster last year, and several of those challenging supply chain conditions will persist into 2023 and beyond. The following is a high-level summary of supply chain challenges and their effects on operational continuity in the water sector. The February 2022 Russian invasion of Ukraine exacerbated existing COVID-19-related stress on commodity markets, triggering price shocks in food and fuel. The reduction in natural gas exports from Russia has caused significant increases in the cost and availability of anhydrous ammonia—prices have spiked over last year to roughly $1,400 per ton in late 2022. This has direct budgetary impacts on water treatment operations, especially systems that use chloramines as a disinfectant. Also, Russia is the world's largest producer of fertilizer, and reductions in fertilizer exports have had far-ranging effects. Shifts in fertilizer markets have caused China—the world's largest exporter of phosphorus—to restrict exports in 2023. In addition to escalating costs, water systems in several states have reported availability issues with phosphate corrosion inhibitors. In mid-2022, a long-term railroad labor dispute resulted in government intervention to negotiate a contract. An 11th-hour agreement in September averted a strike that came very close to cutting off the supply of chlorine and other critical treatment products that are transported by rail. Subsequent votes by the various labor unions to ratify terms had mixed results and again threatened a strike in early December. Water sector associations urged President Biden and Congress to intervene, and ultimately Congress passed legislation that prevented a nationwide rail strike; it should be noted that the contract will end in 2024. Policy factors have also complicated supply chain issues. The US Environmental Protection Agency (EPA) proposed new rules in 2022 that could have direct impacts on the water sector. The most concerning change was the proposal to ban the use of asbestos diaphragms in chlorine production, which would affect 50% of the retail market that supplies the water sector. This rule would require chlor-alkali plants to switch to an alternative method within two to three years, with an estimated cost burden that is 119,000–287,000 times greater than the expected health benefits. Water associations called on EPA to provide a more reasonable timeline for the transition to ensure the availability of chlorine for water sector operations. This request noted the statutory obligation that EPA has under Section 1441 of the Safe Drinking Water Act to ensure the reasonable availability of critical drinking water and wastewater treatment chemicals and materials. This regulatory pressure is amplified by external factors and basic economic principles. Overall demand for various materials slumped during the height of the pandemic. In late 2021, as economic activity returned, the demand for products quickly outpaced supply. Currently, pipe manufacturers are reporting delivery timelines of 15–24 months, and similar delays in other manufactured goods have been observed. If you factor in the massive infusion of federal infrastructure funds for projects of all types, including water-related improvements, the inflationary impacts are notable. The boost in funding for infrastructure programs is welcomed, but the reality is that current economic conditions mean utility customers will be paying more for less. Chemical supply is a prime example of recent challenges. Numerous systems throughout the nation experienced significant delivery disruptions and major spikes in the unit cost of chlorine. AWWA has found that the average cost for each ton of chlorine delivered has increased more than 120%. That alone has had significant budgetary impacts on many water systems and ultimately the rate payers. Last year, one southeastern utility reported that it recently spent an additional $1 million on chlorine—money that will not be spent on operations and maintenance needs. In some instances, chlorine production has been reduced because of disasters, equipment malfunctions, and facility closures. As a result, systems must adjust to chemical costs that are 10 times what systems budgeted. Rate payers will bear the burden of these economic changes. These supply chain issues will likely persist into 2024. Assessing supply chain dependencies will help utilities consider options to mitigate the impacts. Kevin M. Morley is manager of federal relations at the AWWA Government Affairs Office in Washington, D.C. He can be reached at [email protected].

Dose optimization of oil field produced water and advanced water treatment for heavy viscous oil

The treatment and disposal of oil field-produced water from pay zones presents a variety of issues for the hydrocarbon industry. Significant laboratory experimentation is carried out in this research program to design optimized dosages of oil field chemicals to design a water treatment plant for a thin stacked reservoir containing heavy viscous oil. When produced water is produced by pay zones containing heavy viscous oil, treatment can be difficult. For a better understanding of treatment procedures, chemical properties and physical properties of produced water are analysed. For re-injection of producing water to maintain reservoir pressure, the produced water must be compatible with the rheology of the reservoir under study. If the water leaving oil fields is untreated, it creates problems with injectivity loss and formation degradation, contaminating local groundwater resources and causing a significant environmental disaster. When significant amounts of oil field water is generated, the cost of water treatment chemicals rises dramatically. As a result, after examining the ionic concentration of generated water, this research effort recommends optimizingchemical dosing. Various filtration tests for effective rock fluid compatibility, include series, care, and coarse. The entire water treatment system was designed on prescribed treatment chemical dosages. The primary phase of generated water purification in this study relies heavily on the water treatment technologies of coagulation and flocculation. This processed oil field-producedwater is ideal for Enhanced Oil Recovery such as Alkali Surfactant-Polymer flooding.

Cholera outbreak investigation report in Mille woreda, Afar region, Ethiopia, 2019

Introduction: Cholera has remained as one of the important public health problems in Asia and Africa causing substantial morbidity and mortality. Although the burden is greatest in low-income populations with poor access to safe water, and sanitation, cholera is also an important health problem globally. Cholera occurs both as a short outbreak and protracted epidemic/pandemic and when uncontrolled; is devastating to communities and to their prospects for development. To respond quickly and control the outbreak, investigation is crucial; identify risk factors that cause the outbreak, and suggest prevention and control measures. Objective: To identify risk factors and etiology of diarrheal disease outbreak and suggest prevention and control measures in Mille woreda, Afar region Ethiopia, May- June, 2018. Method: Descriptive followed by unmatched case-control study with 1:2 ratio were conducted from May-June 2018. A total of 68 patients and 136 controls were enrolled. A structured interviewer-administered questionnaire was used and medical records and line lists review. Simple random sampling was used to select controls and the first 68 cases. Data were analyzed by SPSS and presented using odd ratio, and tables. Environmental and patient samples were collected for culture and rapid diagnostic test. Result: The investigation identified 229 cholera patients, including 22 rapid diagnostic test confirmed patients and seven culture confirmed patients (attack rate: 8.31%, 229/27,562). Index patient were imported from epi-linked woreda. Diglena geraro kebele were the Epicenter of the outbreak. Epicure trend shows common source infection. Using bifurcation of Awash River for drinking, use untreated/ uncoiled water, poor hand washing practices, and close contact with cholera sick person were found to be associated with cholera. Conclusion: This outbreak was caused by vibrio cholera 01 secondary to drinking water from a bifurcation of Awash River and using untreated water. Contact with diseased person, and use untreated/ uncoiled water was associated with being patients. In order to reduce the risk of cholera, safe drinking water or water treatment chemicals needs to be provided to communities.

Bio-flocculation of Microcystis aeruginosa by using fungal pellets of Aspergillus oryzae: Performance and mechanism

Algal blooms caused by eutrophication are global phenomena that seriously threaten the sustainable use of freshwater resources. Traditional water treatment chemicals often typically lead to high levels of residue and cause damage to the morphology of algal cells. This study investigated an eco-friendly fungal bio-flocculant, Aspergillus oryzae, to remove the representative microalgae (Microcystis aeruginosa). Furthermore, it explored crucial flocculation parameters, adsorption kinetics, and thermodynamics of microalgae using A. oryzae. Accordingly, a flocculation efficiency of >95% was achieved when the fungus was cultured for six days, flocculant dosage was 11 g/L, rotation speed was 100 rpm, temperature was 25 °C, flocculation time was 5 h, and pH ranged between 4.0 and 9.0. KEGG analysis based on the genomic data, and chemical composition analysis revealed that proteins and polysaccharides were the major components of metabolites. Zeta potential analysis, scanning electron microscopy, three-dimensional fluorescence, X-ray spectroscopy, and infrared spectroscopy, electrostatic attraction revealed that electrostatic attraction promoted the destabilization and aggregation of microalgae. Additionally, hyphal surface adsorption and chemisorption from extracellular proteins and exopolysaccharides aided in the removal of microalgae. Therefore, fungi-based bio-flocculants have the potential to remove microalgae in a simple, effective, and eco-friendly manner without the complex extraction of extracellular metabolites.

Business Roundup

BUSINESS Business Roundup ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2022, 100 (20), p 13June 6, 2022Cite this:C&EN 100, 20, 13AbstractSolenis has purchased the Turkish specialty chemical maker Neu Kimya. Neu Kimya’s offerings include chemicals for oil, gas, and water treatment, primarily for markets in the Middle East and southeastern Europe. Chemours says demand for green hydrogen has it considering expanding capacity for ionomer products in Europe and the US. The ionomers are used in Chemours’s Nafion membranes, which go in electrolyzers that turn water to hydrogen and in fuel cells that convert H 2 to power. Sumitomo Chemical and Newlight Technologies plan to launch polypropylene compounds for auto and textile applications based on Newlight’s AirCarbon material. In the firm’s process, microorganisms convert methane into polyhydroxybutyrate. Johnson Matthey has acquired a 4.3% stake in Enapter, which develops anion-exchange membrane electrolyzers for producing green hydrogen, for $21 million. The German firm will use JM’s catalysts to make its electrolyzers. EuroAPI says it will develop lipid nanoparticles to support Sanofi’s efforts toView: PDF | Full Text HTML

Typology of Smallholder and Commercial Shrimp (Penaeus vannamei) Farms, including Threats and Challenges in Davao Region, Philippines

The shrimp industry in the Philippines plays a vital role in the local and national economy through exports to markets abroad such as South Korea, Japan, the USA, and others. In this study, we aimed to describe the various cultural and operational characteristics of smallholder and commercial shrimp (P. vannamei) farms in the Davao region. We also evaluated the current risks and challenges faced by the shrimp farmers. A semi-structured questionnaire that focused on shrimp farmers and operators in the region was used to collect data from N = 41 farmers and operators. The results showed that respondents who were engaged in smallholder farming activities had an average yield of 10 tons/ha. The commercial farms that operate intensively had an average yield of 24 tons/ha. Most smallholder operators used electric generator machines to conduct aeration in their farms using paddlewheels and blowers. More paddlewheels and blowers were employed per pond in the commercial farms compared to smallholder farms. Generally, the income of a farm was related to their yield or the number of fries rather than social factors or their size. In terms of input costs, feeds were found to have the highest cost, followed by the fry, fuel, labor, and others (fertilizers and water treatment chemicals). Most of the farmers mentioned that their shrimp are affected by diseases such as white spot syndrome (60%), black gills (35%), and red tail (5%). They perceived that the main contamination comes from the water source (31%). The main threats mentioned were declining shrimp prices in the market, source of fry, water disposal, overstocking, and water quality. This study shows that small-holding fish farmers should be supported by the government so that they can make use of the more advanced technology employed by commercial shrimp farmers in order to increase their economic productivity and lower their environmental footprint.

Components and Chemicals

Selecting the right pump materials can improve the efficiency and performance of equipment and processes. This article examines common pump component materials and their suitability for handling chemicals in water treatment, food production and clean in place applications.

Suitability of water treatment chemicals in the remediation of produced water: a data-driven approach

There exist numerous counts of research works on produced water. We got to know about them because they made it to publishing probably by indicating a positive or promising result. Contrarily, there exist a hundred times unpublished, unreported works on produced water; works rejected based on not yielding desirable results or not being innovative enough. We might have encountered undesirable results but to what depths and time have we committed to mining out intricate details. The world is thinking and demanding sustainability. Is it sustainable for the future of water treatment, the ease and pace at which we transition to the next chemical or treatment option? In this data-centred approach, three common chemicals, aluminium sulphate, ferrous ammonium sulphate and calcium chloride, were used to treat produced water. The collected data (both initial and final analysis) were inferentially analysed. The first statistical analysis was the testing of 2 hypotheses using the Analysis of Variance test. This was done to reveal to compare the dependence of produced water properties on two categorical variables (sample type and treatment chemicals). The second was the test for relevance: correlation and regression analyses. The laboratory experimental analysis revealed that aluminium sulphate was most suitable for the alteration of physical effluent characteristics; ferrous ammonium sulphate for salinity concerns and calcium chloride for a particular heavy metal’s stability. The overall effluent characteristics indicated a greater dependency on ‘sample type’ than ‘treatment chemicals’. Certain produced water properties relationships were highlighted and quantified for instance iron(II) and chloride ion concentrations were dependent on total solids and indicated a significance F of 0.01.

Application of ultra-low concentrations of moderately-hydrophobic chitosan for ultrafiltration membrane fouling mitigation

Membrane fouling is a major obstacle for ultrafiltration (UF) in water treatment. Here, a strategy for fouling mitigation, by applying an ultra-low concentration of moderately-hydrophobic chitosan (MHC) and using a mildly elevated backwash temperature was proposed. The effects of MHC type, concentration, and backwash temperature were investigated in continuous-flow tests using PVDF hollow fiber membranes and model raw water. Compared to the process without MHC, or with the addition of chitosan or conventional coagulant polyaluminum chloride, the MHC-based UF system under optimal conditions (MHC: 0.01 mg/L; backwash water temperature: 40 °C) demonstrated its superiority with reduction of ~55% reversible fouling (RR) and ~80% irreversible fouling (IRR), as well as improved effluent quality. A mechanistic study by experimental analyses and theoretical computations revealed that the improved performance of the MHC-based UF process was attributed to the following: (1) MHC inhibited contaminant accumulation on the membrane through a hydrophilization surface-modification effect on the PVDF; (2) increased backwash temperature promoted fouling release (by destabilizing the cake layer structure) and enhanced the surface-modification effect. The additional cost of MHC dosing and backwash water heating was estimated at ~0.126 Chinese Yuan per ton of produced water, and the environmental risk of applying MHC was lower than that of conventional water treatment chemicals. In summary, the MHC-based process has the potential to be a feasible and cost-effective approach for UF fouling control.

Preliminarily comparative performance of removing bisphenol-S by ferrate oxidation and ozonation

Bisphenol-S (BS) has recently raised public concerns for its adverse effect on the health safety and ecological security. BS concentrations were detected in many water resources, ranging from 10 ng L−1 to 300 μg L−1, so that various purification techniques have been sought to remove BS. This study investigated the performance of ozonation and ferrate oxidation in the degradation of BS since they are both promising oxidants with high redox potential among water treatment chemicals. It was observed that both ozone and ferrate can achieve over 99% of BS concentration reduction and up to 22.5% of DOC reduction for dosing 0.036 mM of either ferrate or ozone. The vibrio fisheri toxicity exhibited a decline in the treated samples after ozonation or ferrate oxidation. According to the mass spectra analyzed, the degradation pathways were proposed and oxidation products (OPs) were identified. BS degradation by ozonation and ferrate oxidation followed a similar route and four common OPs (OP-249; OP-497-a; OP-497-b, and OP-201) were detected. While ferrate treatment produced one more intermediate (OP-217), ozonation did not, which is attributed to the intensified decomposition of BS by ozonation. The major impact of this study is that ferrate treatment is comparable to the ozonation in removing BS, and further research continuing from this study is necessary to explore the BS removal in various waters with more complex matrixes (e.g., high natural organic matter contents), to investigate BS degradation mechanisms in depth, and to conduct pilot-scale and full-scale trials to establish operational database in running ferrate oxidation and/or ozonation for the treatment of BS in practical world.

Use of polyaminoamide dendrimers starting from different core-initial molecules for inhibition of silica scale: Experiment and theory

Silica has been regarded as one of the toughest contaminants in industrial water systems due to scaling. Several reports have shown that different generations of PAMAM are studied for silica scale inhibition efficiency and only the polyamidoamine PAMAM dendrimers with the core of ethylenediamine are discussed. However, hardly any data is available for PAMAMs with different reactive cores. In the light of this, the current work gets involved in the synthesis of amine-terminated dendrimers (PAMAM) of generation 0 G with reactive cores of different carbon chain lengths by divergent method employed to inhibit the growth of silica. The dendrimers of generation 0 G (PAMAM-0 G) with different carbon chain lengths (1,2-Ethylenediamine; 1,3-Diaminopropane; 1,4-Butanediamine and 1,6-Diaminohexane) as the core were synthesized by economical and green approach. The results showed that PAMAM-0 G-Prop was the most effective inhibitor, producing 415 mg/L molybdate reactive silica (83 % of the original quantity) at 40 mg/L after 24 h, an additional 295 mg/L as compared to the control. Also, PAMAMs profoundly affected the morphology of silica particles, resulting in a large quantity of small particles in solutions containing PAMAM-0 G-Prop or PAMAM-0 G-Eth, yet a small number of large ones in solutions containing PAMAM-0 G-But and PAMAM-0 G-Hex. By Molecular dynamics (MD) simulation, the results showed that the adsorption energy of PAMAM-0 G-Prop was greater than that of other PAMAM molecules. The order of adsorption energy of four dendrimers was PAMAM-0 G-Prop > PAMAM-0 G-But > PAMAM-0 G-Eth > PAMAM-0 G-Hex, and was certified by the analysis of correlation function. Finally, the simulation results provided theoretical basis for evaluating the properties of scale inhibitors and synthesizing novel efficient water treatment chemicals.

Spectroscopic Investigation of Entropic Canopy-Canopy Interactions of Nanoparticle Organic Hybrid Materials.

Nanoparticle organic hybrid materials (NOHMs) are self-suspended liquid-like nanoparticle-based functional materials consisting of a surface-functionalized inorganic nanocore and oligomeric or polymeric chains. They often exhibit complex intermolecular and intramolecular interactions among their constituents, resulting in versatile physicochemical characteristics that range from glassy solids to solvent-free nanoparticle fluids. A variety of applications involving NOHMs have been investigated thus far, including thermal management fluids, lubricants, magnetic fluids, nanocomposites, electrolytes, water treatment and biomass pretreatment chemicals, and CO2 capture solvents. In particular, NOHMs have recently been recognized as a promising CO2 capture and utilization medium. To capture CO2 more effectively, a variety of specific functional groups of strong chemical affinity to CO2 can be added to the polymeric canopy (enthalpic contribution), and various steric considerations induced by attractive/repulsive interactions among the nanocores and canopies can be introduced (entropic contribution). These occur while maintaining negligible vapor pressure and enhanced thermal stability. Here, we investigated the canopy dynamics of NOHMs with different-sized SiO2 nanocores, aiming to reveal the hidden nature of the entropic interaction occurring in NOHMs. Pulse-field gradient nuclear magnetic resonance spectroscopy (with 1H) was employed to investigate the canopy dynamics of the NOHMs synthesized using 7, 12, and 22 nm SiO2 particles, and these results were compared with those from a ternary mix of all three sizes of SiO2 nanocores. The self-diffusion coefficient and thermal diffusivity were also evaluated.