scholarly journals Using Molecular Modelling to Understand and Predict the Impact of Organic Additives as Crystal Growth Modifiers

2020 ◽  
Vol 73 (8) ◽  
pp. 724 ◽  
Author(s):  
Franca Jones ◽  
Andrew L. Rohl
Keyword(s):  
Crystal Growth ◽  
Molecular Modelling ◽  
Barium Sulfate ◽  
Organic Molecules ◽  
Adsorption Process ◽  
Organic Additives ◽  
Lattice Matching ◽  
Growth Modification ◽  
Matching Criteria ◽  
The Impact

Empirical molecular modelling was used to investigate the impact of organic additives on crystal morphology and inhibition. The replacement energy was found to correlate reasonably well with the degree of inhibition as determined from conductivity data. The replacement energy was also able to predict the barium sulfate face on which additive adsorption was most likely. While the ability of the organic functional groups to sit in the vacant sulfate lattice positions (the so-called ‘lattice matching’ criteria) appears intuitively sensible, it was found that this is not a sufficient criterion to predict real behaviour. A better criterion is the overall replacement energy as it takes into consideration the number of Ba–Oorganic interactions and whether the adsorption process overall is energetically favourable (by including the hydration energy of the ions). Thus, the replacement energy can successfully predict the effect of organic molecules on the crystal growth modification of barium sulfate.

scholarly journals Graphene-Based Materials Immobilized within Chitosan: Applications as Adsorbents for the Removal of Aquatic Pollutants

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3655
Author(s):  
Daniele C. da Silva Alves ◽  
Bronach Healy ◽  
Tian Yu ◽  
Carmel B. Breslin
Keyword(s):  
Mechanical Properties ◽  
Heavy Metal Ions ◽  
Chelating Agents ◽  
Organic Molecules ◽  
Adsorption Process ◽  
Chitosan Hydrogel ◽  
Polymeric Blends ◽  
Aquatic Pollutants ◽  
Immobilization Matrix ◽  
Adsorbent Materials

Graphene and its derivatives, especially graphene oxide (GO), are attracting considerable interest in the fabrication of new adsorbents that have the potential to remove various pollutants that have escaped into the aquatic environment. Herein, the development of GO/chitosan (GO/CS) composites as adsorbent materials is described and reviewed. This combination is interesting as the addition of graphene to chitosan enhances its mechanical properties, while the chitosan hydrogel serves as an immobilization matrix for graphene. Following a brief description of both graphene and chitosan as independent adsorbent materials, the emerging GO/CS composites are introduced. The additional materials that have been added to the GO/CS composites, including magnetic iron oxides, chelating agents, cyclodextrins, additional adsorbents and polymeric blends, are then described and discussed. The performance of these materials in the removal of heavy metal ions, dyes and other organic molecules are discussed followed by the introduction of strategies employed in the regeneration of the GO/CS adsorbents. It is clear that, while some challenges exist, including cost, regeneration and selectivity in the adsorption process, the GO/CS composites are emerging as promising adsorbent materials.

scholarly journals Single Crystal Growth and Physical Properties of Pyroxene CoGeO3

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 378
Author(s):  
Li Zhao ◽  
Zhiwei Hu ◽  
Hanjie Guo ◽  
Christoph Geibel ◽  
Hong-Ji Lin ◽  
...  
Keyword(s):  
High Pressure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Crystal Growth ◽  
Physical Properties ◽  
Single Crystal ◽  
Single Crystals ◽  
Magnetic Moments ◽  
Single Crystal Growth ◽  
The Impact

We report on the synthesis and physical properties of cm-sized CoGeO3 single crystals grown in a high pressure mirror furnace at pressures of 80 bar. Direction dependent magnetic susceptibility measurements on our single crystals reveal highly anisotropic magnetic properties that we attribute to the impact of strong single ion anisotropy appearing in this system with TN∼33.5 K. Furthermore, we observe effective magnetic moments that are exceeding the spin only values of the Co ions, which reveals the presence of sizable orbital moments in CoGeO3.

scholarly journals Synthesis of magnesium carbonate hydrate from natural talc

2020 ◽  
Vol 18 (1) ◽  
pp. 951-961
Author(s):  
Qiuju Chen ◽  
Tao Hui ◽  
Hongjuan Sun ◽  
Tongjiang Peng ◽  
Wenjin Ding
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Crystal Growth ◽  
Crystal Morphology ◽  
Magnesium Carbonate ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
Morphological Transformation ◽  
X Ray ◽  
Carbonation Process

AbstractVarious morphologies of magnesium carbonate hydrate had been synthesized without using any organic additives by carefully adjusting the reaction temperature and time during the talc carbonation process. At lower temperatures, magnesium carbonate hydrate was prone to display needle-like morphology. With the further increase of the carbonation temperature, the sheet-like crystallites became the preferred morphology, and at higher aging temperatures, these crystallites tended to assemble into layer-like structures with diverse morphologies, such as rose-like particles and nest-like structure. The reaction time had no effect on the crystal morphology, but it affected the particle size and situation of the crystal growth. X-Ray diffraction results showed that these various morphologies were closely related to their crystal structure and compositions. The needle-like magnesium carbonate hydrate had a formula of MgCO3·3H2O, whereas with the morphological transformation from needle-like to sheet-like, rose-like, and nest-like structure, their corresponding compositions also changed from MgCO3·3H2O to 4MgCO3·Mg(OH)2·8H2O, 4MgCO3·Mg(OH)2·5H2O, and 4MgCO3·Mg(OH)2·4H2O.

FC 096THE EFFECT OF INCREMENTAL START OF HAEMODIALYSIS ON BLOOD PRESSURE AND INTERDIALYTIC WEIGHT GAIN: PRELIMINARY FINDINGS FROM THE ENDURE STUDY

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Adil Hazara ◽  
Victoria Allgar ◽  
Maureen Twiddy ◽  
Sunil Bhandari
Keyword(s):  
Blood Pressure ◽  
Propensity Scores ◽  
Phase 1 ◽  
Tertiary Care ◽  
Residual Renal Function ◽  
Care Hospital ◽  
Interdialytic Weight Gain ◽  
Matching Criteria ◽  
The Impact

Abstract Background and Aims Mortality rates are high in patients starting haemodialysis/haemodiafiltration (HD) therapy. Incremental HD may help reduce this risk by reducing the burden of early treatment whilst patients are still adapting to long-term HD therapy. A feasibility study (ENDURE study – Clinical trials ID: NCT04268264) is being conducted with the primary objectives of evaluating the acceptability and tolerance of a new incremental HD regime. Its secondary aims are to evaluate the impact of this form of incremental HD on indicators of patient safety and wellbeing. These indicators include blood pressure (BP) control and interdialytic weight gains (IDWG) which are independently associated with adverse cardiovascular outcomes in patients on long-term HD. We present preliminary findings from the study related to systolic BP and IDWG. Method The ENDURE study is being carried out at a tertiary care hospital in the United Kingdom. Patients aged > 18 years known to renal services for at least 90 days, referred for start of HD, were eligible for participation. Following approved consenting procedures, they are started on a new regime of incremental HD starting dialysis twice weekly with progressive increases in the duration and frequency of sessions over 15 weeks. This period is split in to four phases; phase 1 representing the first two days of dialysis (baseline) whereas phases 2 – 4 representing the pre-specified incremental steps. Propensity scores were calculated to match each participant (incremental HD group) with two controls from a database of patients who previously started HD at our centres using the standard protocol of 3 times weekly, 4hr long sessions. The matching criteria accounted for 14 key demographic, clinical and laboratory characteristics. Results were analysed as intention to treat. In comparing BP and IDWG between the two groups, only readings taken pre-dialysis at the first session of the week was considered. This study has been approved by the West of Scotland Research Ethics committee-4 (Ref: 19/WS/0019). Results Baseline characteristics of the first 15 participants (target 20) and their matched controls are presented in table 1. The proportion of females and duration of previous specialist input was higher in the incremental HD group. Conclusion The ENDURE study tests the feasibility of starting patients on a novel incremental HD regime. Early data suggest that control of systolic BP and IDWG are comparable to patients who start dialysis at 3 times weekly. Further work is needed to understand the impact of reducing dialysis frequency on BP control correlating the findings with changes residual renal function and objective measures of fluid overload.

Experimental Study of Natural Ions and Rock Interactions for Seawater Breakthrough Percentage Monitoring during Offshore Seawater Flooding

SPE Journal ◽  
2021 ◽  
pp. 1-21
Author(s):  
Yanqing Wang ◽  
Xiang Li ◽  
Jun Lu
Keyword(s):  
Porous Media ◽  
Fluid Flow ◽  
Barium Sulfate ◽  
Large Deviation ◽  
Exchange Process ◽  
Reaction Model ◽  
Sodium Content ◽  
Flow In Porous Media ◽  
Formation Water ◽  
The Impact

Summary Seawater breakthrough percentage monitoring is critical for offshore oil reservoirs because seawater fraction is an important parameter for estimating the severity of many flow assurance issues caused by seawater injection and further developing effective strategies to mitigate the impact of those issues on production. The validation of using natural ions as a tracer to calculate the seawater fraction was investigated systematically by studying the natural chemical composition evolution in porous media using coreflood tests and static bottle tests. The applicable range of ions was discussed based on the interaction between ion and rock. The barium sulfate reactive model was improved by integrating interaction between ions and rock as well as fluid flow effect. The results indicate that chloride and sodium interact with rock, but the influence of the interaction can be minimized to a negligible level because of the high concentrations of chloride and sodium. Thus, chloride and sodium can be used as conservative tracers during the seawater flooding process. However, adsorption/desorption may have a large influence on chloride and sodium concentrations under the scenario that both injection water and formation water have low chloride and sodium content. Bromide shows negligible interaction with rock even at low concentrations and can be regarded as being conservative. The application of a barium and sulfate reaction model in coreflood tests does not work as well as in bottle tests because fluid flow in porous media and ion interaction with rock is not taken into account. Although sulfate and barium adsorption on clay is small, it should not be neglected. The barium sulfate reaction model was improved based on the simulation of ion transport in porous media. Cations (magnesium, calcium, and potassium) are involved in the complicated cation-exchange process, which causes large deviation. Therefore, magnesium, calcium, and potassium are not recommended to calculate seawater fraction. Boron, which exists as anions in formation water and is used as a conservative tracer, has significant interactions with core matrix, and using boron in an ion tracking method directly can significantly underestimate the seawater fraction. The results give guidelines on selecting suitable ions as tracers to determine seawater breakthrough percentages under different production scenarios.

scholarly journals The Impact of Organic Additives on Copper Trench Microstructure

2017 ◽  
Vol 164 (9) ◽  
pp. D543-D550 ◽  
Author(s):  
James B. Marro ◽  
Chukwudi A. Okoro ◽  
Yaw S. Obeng ◽  
Kathleen C. Richardson
Keyword(s):  
Organic Additives ◽  
The Impact

scholarly journals Reuse of Newspaper As An Adsorbent For Cu (II) Removal By Citric Acid Modification

2018 ◽  
Vol 156 ◽  
pp. 02012 ◽  
Author(s):  
Mardiah ◽  
Rif’an Fathoni ◽  
Pratiwi Pudyaningtyas ◽  
Hamdania Gamu ◽  
Rinaldy
Keyword(s):  
Citric Acid ◽  
Adsorption Process ◽  
Kinetic Studies ◽  
Order Reaction ◽  
Acid Modification ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo Second Order ◽  
Heavy Metal Adsorbent ◽  
The Impact

High Consumption of paper, bring the impact of the waste paper itself. And the utilization of the paper is limited to recycled products and crafts, whereas paper such as newspaper still contains cellulose that can be potential to be used as a heavy metal adsorbent. In this study, newspaper was dissolved in sodium bicarbonate to reduce various impurities and then was reacted with citric acid (CA). The modified adsorbent was characterized by FTIR and was tested for adsorb Cu(II) in artificial solution. After adsorption process, the solution was filtered and analysed using Atomic Absorption Spectrophotometer (AAS). The adsorption experimental data was fitted to Langmuir, Freundlich, Tempkin, and Dubinin-Radushkevich for equilibrium model and was fitted to pseudo first order reaction and pseudo second order reaction for kinetic studies. The result showed that CA-modification newspaper able to remove heavy metals Cu(II) in solution.

A Study on Adsorption Ammonia Nitrogen of Diatomite Modified by Microwave

2012 ◽  
Vol 602-604 ◽  
pp. 1211-1214
Author(s):  
Zhi Wen Luo ◽  
Zhong Chen ◽  
Su Hong Liu
Keyword(s):  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Nitrogen Adsorption ◽  
Microwave Treatment ◽  
Ammonia Nitrogen ◽  
Ammonia Adsorption ◽  
Freundlich Isotherms ◽  
Adsorption Capacities ◽  
The Impact ◽  
Modified Diatomite

Diatomite was modified by microwave treatment to increase their utilization value, using modified diatomite to treat ammonia-nitrogen wastewater. The experiment indicated that adsorption process of modification of the modified time by microwaves and microwave power is the impact of ammonia adsorption of the main factors. Through modification experiments by raising the capacity of diatomite adsorption ammonia nitrogen, adsorption of ammonia nitrogen increase over one time. Langmuir and Freundlich isotherms were used to fit and the experimental results show that the modified diatomite adsorption onto ammonia nitrogen accords with Langmuir and Freundlich isotherm. The maximum theoretical adsorption capacities are 5.81083mg/g.

scholarly journals Does Social Franchising Private Health Facilities Shift Consumers Budget Line? An Econometric Analysis of the Average Treatment Effect within Private Health Facilities in Embu County, Kenya

2020 ◽  
Vol 6 ◽  
pp. 1
Author(s):  
Stephen Nyag ◽  
Susan Okeri ◽  
◽  
Keyword(s):  
Average Treatment Effect ◽  
Health Facilities ◽  
Sub Saharan Africa ◽  
Social Franchising ◽  
Cost Variance ◽  
Matching Criteria ◽  
The Cost ◽  
The Impact ◽  
Radius Matching

The Kenyan private health sector is one of the most developed in Sub-Saharan Africa and is highly critical in healthcare delivery. It is estimated 47 percent of the first quintile of income earners utilize the private facility for healthcare needs and 33 percent of women seek family planning (FP) services in this sector. However, the cost of healthcare services has been a great impediment to service utilization. To improve service quality and increase access, social franchising, interventions on the demand side such as the use of insurance and vouchers, and supply of subsidized medical products on the supply side are intended to reduce the cost of services. This study sought to investigate the impact of interventions of social franchisors on the cost of healthcare in private facilities in Kenya. The study used primary data collected from 215 individuals living within catchment areas with private health facilities using researcher-administered questionnaire. The main franchisors included in this study were Sustainable Health Foundation (CFW) and Population Services Kenya (Tunza). Results revealed that women whose primary motivation to visit private facilities included FP services, need of a lower cost of treatments, and quality services had higher odds of choosing franchised health facilities. Propensity score matching (PSM) using three matching criteria—nearest neighbor, kernel matching, and radius matching of 0.01—indicated that individuals seeking children’s health services and 3-month FP methods paid similar amounts in either franchised or nonfranchised health facilities. However, there was a huge cost variance for long-term FP methods where women paid significantly less, implying that social franchisors’ main impact is on long-term FP methods. The cost variance was due to vouchers utilized by some respondents hence, incurring zero cost in franchised facilities. Therefore, the study recommends the expansion of social franchising membership and the use of the voucher system for financially incapable consumers.

scholarly journals Zeolites as alcohol adsorbents from aqueous solutions

2006 ◽  
pp. 83-87 ◽  
Author(s):  
Blagica Cekova ◽  
Dragi Kocev ◽  
Elena Kolcakovska ◽  
Daniela Stojanova
Keyword(s):  
Heat Treatment ◽  
Aqueous Solutions ◽  
Pore Volume ◽  
Industrial Wastewater ◽  
Organic Molecules ◽  
Adsorption Process ◽  
Aqueous Acetone ◽  
Heats Of Adsorption ◽  
Series Of Experiments ◽  
Low Costs

The potential usage of zeolites as adsorbents for the removal of organic molecules from water was investigated in a series of experiments with aqueous solutions of lower alcohols. This could represent a simple solution to the problem of cleaning up industrial wastewater as well as recovering valuable chemicals at relatively low costs. Adsorption isotherms of the Langmuir type were applied, and calculations showed that the amount of propanol adsorbed on silicalite corresponded to approximately 70% of the pore volume. The adsorption process is simple, and recovery of the more concentrated products is easily done by heat treatment and/or at lowered pressures. Adsorption experiments with aqueous acetone showed that silicalite had approximately the same adsorption capacity for acetone as for n-propanol. Heats of adsorption were determined calorimetrically.

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