Different Kinds Of Water Research Articles

A new strategy to construct MOF-on-MOF derivatives for the removal of tetracycline hydrochloride from water by activation of peroxymonosulfate

A MOF-on-MOF composite derivative material named ZIF-67@Ce-MOF-600 was designed and synthesized. The preparation of ZIF-67@Ce-MOF-600 was optimized from the aspects of the ratio of metal and ligand, heat-treatment temperature. It was demonstrated by XRD, FT-IR, SEM-EDS and TEM. The optimum conditions for the activation of PMS by ZIF-67@Ce-MOF-600 for the degradation of tetracycline (TC) were investigated by adjusting the catalyst dosage, TC, pH, peoxymonosulfate (PMS) concentration, and different kinds of water, co-existing anions and pollution. Under optimal conditions (20 mg catalysts and 50 mg PMS added) in 100 mL of tetracyclines (TC) solvent (20 mg TC/L), the removal rate could reach up to 99.2% and after five cycles was 70.5%. The EPR results indicated the presence of free radicals and non-free radical, among which free radicals intended to play a major role in the degradation process. Its possible degradation pathways and attack sites were analyzed by liquid-phase mass spectrometry and DFT analysis.

Synthesis of hybrid azobenzene-chalcone dyes and studies on their photophysical properties: Molecular recognition of carbonate and phosphate ions using a novel turn-off fluorescent probe

The work presented here describes the synthesis and comparative physiochemical studies of hybrid compounds C-1 to 5 of azobenzene A-1 and chalcone B-1, which exhibited the characteristic of both. Further, electron-withdrawing and donating substituents analogues have also been synthesized. The hybrid compound is unique in nature because it contains the phenolic -OH, -N = N-, as well as α,β-unsaturated enone functional groups. The photophysical properties of hybrid C-1 behaved more or less like the azobenzene moieties and showed the same pattern of UV–vis absorption as with the change in the polarity of the solvent and the change in the pH of the medium. Thus, in the non-polar solvent or in the water medium, the phenol form dominates with its yellow colour and in polar solvents shows an intense red colour of keto form. They show a dramatic quenching of fluorescence emission in the polar solvent. Furthermore, after screening, C-1 was found to show selective sensing of the aqueous CO32− ion as well as minimally with PO43- and show a characteristic colour change in an organic solvent such as CH3CN. A few ions also changed colour in DMF, but that was due to the only shifting of the tautomerization equilibrium from keto to enol form. The UV–vis as well as fluorescent spectral studies, determination of the detection limits, and binding constants illustrated significant sensing of CO32− ions. A systematic study was performed to understand the binding interactions of the chemosensor by using Job's plot and time-dependent 1H NMR studies that supported the involvement of phenoloc -OH and β carbon of α,β-unsaturated system. The characteristic pattern of UV–vis and interaction mode was confirmed by DFT studies. The applicability of chemosensor C-1 was demonstrated by the development of a paper strip model to check the presence of CO32− ions in different kinds of water in society.

A Novel Coupler of Capacitive Power Transfer for Enhancing Underwater Power Transfer Characteristics

Compared to inductive power transfer (IPT) technology, capacitive power transfer (CPT) technology offers unique advantages such as being cost-effective, lightweight, and free from eddy-current losses, making it more suitable for underwater power transfer. Unlike air, water can conduct electricity and the electric conductivity of different kinds of waters varies with different ion concentrations, which would greatly affect the equivalent model of the underwater couplers. To address this issue, multiple types of underwater coupler working in different kinds of water are compared and analyzed. The influence of the electrical conductivity of water on the capacitive coupler is comprehensively analyzed, and the novel capacitive coupler and its equivalent model are proposed to improve power transfer efficiency. To verify the theoretical analysis, the double-sided LC-compensated CPT circuit is built and tap water is used in the experiment. The experimental results are consistent with the theoretical analysis. In addition, the experimental results also validate the superiority of the proposed capacitive coupler compared to existing research.

Design And Development Of A Spiral Tube Water Wheel Pumping System: A

This paper provides an overview of the ancient evolution,design and development of different types of spiral tube water wheel pumping system (STWWPS). It has always been a challenge to lift water and carry it to some other locations for executing meaningful work, making use of the alternative sources of power. Several kinds of non-conventional energy sources and techniques have been tried. Each one is having its own merits and demerits. Making use of the kinetic energy of flowing water can be achieved through different kinds of water wheel.Spiral tube powered by kinetic energy of flowing water has been utilized for lifting and carrying water for irrigation and other purposes, contributing to the replacement of conventional diesel and electric power sources. These conventional sources are expensive (Diesel) and often unreliable in rural areas (Electricity).This review paper examines the design, development, and performance evaluation of various spiral tube pumping systems, including single, double, multilayer, pedal type, four scoop type, and multi-purpose models. It examines the load torque, power, efficiency, and stress analysis of shaft and bearing, and the impact of rotational speed, submerged ratio, and number of spiral pipes on the performance of the pumping system.The working principle allows these pumps to create a column of water within its coil that alternatively the air which is compressed as it moves towards the center of wheel. These pumpsnot only save electricity and diesel cost but the maintenance cost is also lowapart from contributing to the clean environment.

Research on Improvement of Detection of Pb2+ in Environment Waters by Graphene/Nafion Modified Glassy Carbon Electrode

Abstract An electrochemical determination of Pb2+ by cyclic voltammetry, differential pulse voltammetry, and differential pulse anodic stripping voltammetry in various waters using a glassy carbon electrode modified with graphene/Nafion mixture has been developed. A series of optimum conditions such as graphene concentration, modifying amount, Nafion concentration, scanning speed, pH, accumulation potential, and time were optimized. Under optimal experiments, some evaluation indexes were analyzed. Graphene/Nafion/GCE was successfully used in the detection and quantification of Pb2+ in various real water samples using three methods above. Differential pulse anodic stripping voltammetry method that is adopted to study the linear range and the detection limit for Pb2+ proved to be more effective than the other two. The wider range is 0.02-24.15 μM, the lower detection limit is 5.1mM, and the recovery is 96.1-109.0%. This will provide a theoretical basis and the practical method for the analysis of heavy metal polltants in different kinds of water.

Influence of ozone microbubble enhanced oxidation on mine effluent mixes and Daphnia magna toxicity

The mining industry often must mix different kinds of water on the mine site during pre-treatment or post-treatment before the final discharge of the treated water to the environment. Microbubble ozonation has proven to be efficient in the removal of contaminants of concern from mine water, such as metals, metalloids, and nitrogen compounds, which can persist in the environment and entail toxicity issues. This study evaluated the efficiency of ozone microbubbles combined with lime precipitation on contaminant removal and its impact on toxicity for Daphnia magna with five different mine effluent mixes from an active mine site located in Abitibi-Témiscamingue, QC, Canada. For the non-acidic mixes, two scenarios were tested: first, pre-treatment of metals using lime precipitation and a flocculant was conducted prior to ozonation; and second, ozonation was conducted prior to metals post-treatment using the same precipitation and flocculation technique. Results showed that the NH3–N removal efficiency ranged from 90% for the lower initial concentrations (1.1 mg/L) to more than 99% for the higher initial concentrations (58.4 mg/L). Moreover, ozonation without metals pre-treatment improved NH3–N treatment efficiency in terms of kinetics but entailed abnormal toxicity issues. Results of bioassays conducted on water with metals pre-treatment did not show any toxicity events but showed abnormal toxicity patterns on the mixes treated without metals pre-treatment (diluted effluents were toxic, while undiluted were not). At 50% dilution, the water was toxic, probably due to the potential presence of metal oxide nanoparticles. The confirmation of the source of toxicity requires further investigation.

Influence mechanism of groundwater on the carbon cycle in alkaline lakes

The discharge of groundwater to the lake is a mixed process of two different kinds of water, and the hydrochemical action at the contact interface of them may lead to the migration and transformation of carbon. However, the input of carbon from groundwater to surface water is usually measured by the product of dissolved carbon (DC) concentration and water volume at present, and there are few reports on the physicochemical reactions in the mixing process. In this paper, taking Daihai Lake as an example, the principle of mass conservation and hydrogeochemical simulation were used to construct the carbon balance equation of the groundwater and lake water mixing zone, and the mechanism of carbon fixation and emission in the mixing process was analyzed. The results show that the precipitation of calcium carbonate was the main hydrochemical reaction controlling the migration and transformation of dissolved inorganic carbon (DIC) after mixing groundwater with alkaline lake water. A large amount of HCO3– in the lake was transformed into CaCO3 and CO2 under the action of groundwater. The total amount of DIC discharged by groundwater to Daihai Lake was 770 t/a. Due to the water chemical reaction at the interface between groundwater and lake water, the carbon removed by CaCO3 precipitation and CO2 emission was 645 t/a respectively. The mixture of the two kinds of water resulted in a net reduction of 520 t/a of DIC in Daihai Lake. Ca2+ concentration in groundwater was the main factor affecting DIC migration and transformation in the mixing process of the groundwater and lake water. With the increase of Ca2+ concentration in groundwater, more carbon in the form of HCO3– would be separated from lake water. This study has important significance for revealing the impact of groundwater on the lake carbon cycle and the role of groundwater in the global carbon cycle.

Release of microfibers from surgical face masks: an undesirable contributor to aquatic pollution

The worldwide usage of surgical face masks (SFM) has increased rapidly during the COVID-19 pandemic. Its degradation possibly produces billions of microplastics (MPs) in the environment. To quantify the release of microfibers (MFs), unused SFM were treated with eight different aqueous solutions, each with five replications in two categories, i.e., freshwater (FW) treatments [800 mL FW, 40 mL of 95% alcohol + 800 mL FW, 40 mL of 30% H2O2 + 800 mL FW, and 4 g sodium dodecyl sulfate (SDS) + 800 mL FW], and saltwater (SW) treatments (800 mL SW, 40 mL of 95% alcohol + 800 mL SW, 40 mL of 30% H2O2 + 800 mL SW, and 4 g SDS + 800 mL SW) at 25 °C for 60 days. The predominant MFs disposed from SFM were transparent and sized between 1.0 to < 0.5 mm. The mean highest amount of MFs observed was 4,911.3 (1-day) and 6,180.24 (30-day) in sodium dodecyl sulfate (SDS) mixed with SW, and 7,269.7 (60-day) in SDS with FW. The greatest number of MFs released per day was 275 (SDS in SW), followed by 193 (SDS in FW). The results indicated that if different kinds of water are mixed with detergent (SDS), it could accelerate the disposal of MP, whereas SW has considerably higher ability to release more MFs in a shorter time period compared to FW. Furthermore, this study implied that the inappropriate dumping of SFM could unfortunately escalate the preexisting MP pollution in the aquatic environment, which could negatively affect the aquatic living beings.

Use of Passive and Grab Sampling and High-Resolution Mass Spectrometry for Non-Targeted Analysis of Emerging Contaminants and Their Semi-Quantification in Water.

Different groups of organic micropollutants including pharmaceuticals and pesticides have emerged in the environment in the last years, resulting in a rise in environmental and human health risks. In order to face up and evaluate these risks, there is an increasing need to assess their occurrence in the environment. Therefore, many studies in the past couple of decades were focused on the improvements in organic micropollutants’ extraction efficiency from the different environmental matrices, as well as their mass spectrometry detection parameters and acquisition modes. This paper presents different sampling methodologies and high-resolution mass spectrometry-based non-target screening workflows for the identification of pharmaceuticals, pesticides, and their transformation products in different kinds of water (domestic wastewater and river water). Identification confidence was increased including retention time prediction in the workflow. The applied methodology, using a passive sampling technique, allowed for the identification of 85 and 47 contaminants in the wastewater effluent and river water, respectively. Finally, contaminants’ prioritization was performed through semi-quantification in grab samples as a fundamental step for monitoring schemes.

Effect of Different Kinds of Water on Growth, Yield and Water Use Efficiency of Soybean

A field experiment conducted at International Crops Research Institutefor the Semi-Arid Tropics (ICRISAT), Patancheru, India to study the effect of different quality of water on growth, yield and water use efficiency of soybean during rabi 2015-16. The experiment was laid out in randomized block design (RBD) and replicated fivetimes with three treatments i.e. untreated wastewater, treated wastewater and fresh water. The result of the present study indicate that untreated wastewater affect plant height, leaf area index, dry matter production, number of pod per plant, test weight, seed yield and straw yield significantly. Highest seed yield of soybean was observed in untreated wastewater (22.20 q ha-1) in relation to wastewater and freshwater. Higher value of growth attributes and yield attributes were found in untreated wastewater. Highest water use efficiency of soybean was also recorded in untreated wastewater treatment. This study, it concluded untreated wastewater increased growth attributes, yield attributes and yield and also water use efficiency due to presence of enough amount of nutrient in untreated wastewater and less amount of heavy metal that help to achieve maximum seed yield and water use efficiency in soybean.

Eco-friendly green synthesis of functionalized mesoporous silica nanospheres for the determination of Al(III) ions in multiple samples of different kinds of water

The current work proposed a new green procedure that is not sophisticated to recognize and determine the Al(III) ions in multiple water samples. The suggested method was conducted based upon the direct immobilization of aurintricarboxylic acid reagent into the mesoporous silica nanospheres to shape a unique and novel solid sensor. Al(III)-ATA red-complex has been formed at pH 4.0 and spectrophotometrically measured at 525 nm. Moreover, the complexation was reversible, and the ATA sensor retained his functionality even after six-time reuse/cycles using EDTA as eluent. Univariate and multivariate (partial least squares 1, PLS-1) calibration techniques were utilized for calculating the figures of merit for the determination of the Al(III) ions. The obtained calibration curve was linear from 2.0 to 70 ppb Al(III) ions concentration. The developed method has a detection limit of 3.5 ppb. In addition, the ATA sensor showed high adsorption capacity value (118.53 mg/g) which gives it a great advantage to be applicable as nanocollector for trapping Al(III) ions. The novel ATA sensor showed high degree of selectivity, sensitivity, reproducibility, and stability. The current study explores the effectiveness of the ATA sensor for the first time to produce a green solid sensor to determine the trace amount of Al(III) in diverse water types; tap, mineral, river, well, and sea water.

Study on properties of bio-bricks

In the age of sustainability, it is necessary to prevent the depletion of natural resources to maintain needs and ecology. Hence, in the process of manufacturing mud and fly ash bio-bricks, materials like fly ash and bacterial solutions (Bacillus Megaterium and Bacillus Subtilis) are widely used. The experiment was carried out at various pH levels (basic, acidic, neutral) and at different temperatures (4, 31, 60 °C) with two different kinds of water (lab grade, groundwater) to find the optimum mix proportion of a brick. Bricks were cast by the MICP method where bio-mineralization (a process that converts CaCl2, urea, and bacteria into CaCO3) takes place. An experimental program has been carried out at various ages of bricks in order to determine the physical and mechanical properties of bricks, such as compressive strength, water absorption, hardness, size, shape, and color. The experiment results are used to determine the effect of bacterial solutions and fly ash content on the unburnt brick’s properties. The bricks tested showed comparatively better properties than the conventional and hence they are good to be used in temporary construction.

Morphologies and Structure of Brain Lipid Membrane Dispersions.

This study aims to explore the variety of previously unknown morphologies that brain lipids form in aqueous solutions. We study how these structures are dependent on cholesterol content, salt solution composition, and temperature. For this purpose, dispersions of porcine sphingomyelin with varying amounts of cholesterol as well as dispersions of porcine brain lipid extracts were investigated. We used cryo-TEM to investigate the dispersions at high-salt solution content together with small-angle (SAXD) and wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) for dispersions in the corresponding salt solution at high lipid content. Sphingomyelin forms multilamellar vesicles in large excess of aqueous salt solution. These vesicles appear as double rippled bilayers in the images and as split Bragg peaks in SAXD together with a very distinct lamellar phase pattern. These features disappear with increasing temperature, and addition of cholesterol as the WAXD data shows that the peak corresponding to the chain crystallinity disappears. The dispersions of sphingomyelin at high cholesterol content form large vesicular type of structures with smooth bilayers. The repeat distance of the lamellar phase depends on temperature, salt solution composition, and slightly with cholesterol content. The brain lipid extracts form large multilamellar vesicles often attached to assemblies of higher electron density. We think that this is probably an example of supra self-assembly with a multiple-layered vesicle surrounding an interior cubic microphase. This is challenging to resolve. DSC shows the presence of different kinds of water bound to the lipid aggregates as a function of the lipid content. Comparison with the effect of lithium, sodium, and calcium salts on the structural parameters of the sphingomyelin and the morphologies of brain lipid extract morphologies demonstrate that lithium has remarkable effects also at low content.

A REVIEW ON THE HAMMAM: A REGIMEN FROM ASCLEPIONS

The bathing was almost universally followed practice in antiquity. It was of religious, cultural as well as therapeutic values. Before scientific medicine, Asclepions were the healing temples, which were always built near a river or spring and worked as today's clinic and hospitals, where water was used for therapeutic purposes. Hippocrates also described the different kinds of water as well as the therapeutic property of bathing. In the Roman and Arabic periods, Hammam was too popular and it was social practice. The bathing Houses were highly sophisticated building. The physicians of medieval age also considered hammam as one of the important resigns in the art of healing. They were described as the different kind of Hammam and their therapeutic importance.

Heating characteristics of igneous rock-forming minerals under microwave irradiation

Microwave-assisted mechanical excavation has been considered as a promising rock breakage method and is widely studied in recent years. Heating characteristics of minerals are the basis of research on the weakening effect of microwave irradiation on rock. In this paper, 14 igneous rock-forming minerals were microwave heated. The influences of microwave power, mineral group/sub-group, element content and water on the heating characteristics of these minerals were analyzed. The results show that the microwave sensitivities of these minerals can be categorized into different levels according to their heating rates. As the microwave power increases, the microwave sensitivity of minerals remains unchanged. Mineral group has the greatest influence on their microwave sensitivities, followed by crystal structure and iron content. In addition, different kinds of water contained in minerals greatly influence their heating characteristics.

A Purely Model-Based Approach to Object Pose and Size Estimation With Electric Sense

In the 50s, biologists discovered that some electric fish is capable of discriminating the pose as well as the electric and geometric properties of surrounding objects by navigating and measuring the distortions of a self-generated electric field. In this article, we address the challenging issue of ellipsoidal objects pose and size estimation for underwater robots equipped with artificial electric sense. Unlike current methods, the approach can estimate both the position and size in parallel with a single straight trajectory. Neither multipolarization nor reactive self-alignment control are necessary to locate the object. The approach is a purely model-based heuristic that selects the best ellipsoid parameters among a set of potential candidates. It is based on a set of four electric measurements recorded at several positions along the robot trajectory along which the displacement is measured. The efficiency of the method is assessed over numerous experiments with different objects, several positions, and orientations, and two different kinds of water (fresh and salt water). Despite some model simplifications and experimental errors, location and size estimation errors are on average below $\text{1}\,$ cm and $\text{15}\%$ , respectively, while offering promising perspectives for real-time computation.

An Improved Predictive Model for Determining the Permeability Coefficient of Artificial Clayey Soil Based on Double T2 Cut‐Offs

Permeability is one of the most important engineering properties of clayey soil. However, the traditional method for determining the permeability coefficient is time‐consuming. To establish a simple and accurate predictive method to obtain the permeability coefficient of artificial clayey soil based on the double cut‐off transverse relaxation times (T2 cut‐offs) using low‐field nuclear magnetic resonance (NMR) technology, eight kinds of artificial clayey soil with different mineralogical compositions were prepared in the laboratory. Evaporation tests at 40°C were carried out on the saturated artificial clayey soil samples in an oven. During the evaporation process, NMR tests were also performed on the artificial clayey soil every hour. The results showed that the evaporation process could be divided into three stages according to different evaporation rates: the constant rate stage (CRS), the falling rate stage (FRS), and the residual stage (RS). The water evaporated in the CRS and FRS was defined as the absolute movable water and the partially movable water, respectively. The water that could not evaporate in the RS was defined as the immovable water. Based on the cumulative signal amplitudes in the T2 spectrum corresponding to different kinds of water, the double T2 cut‐offs were defined. On the basis of the double T2 cut‐offs and T2 spectrum of the saturated sample, an improved Timur–Coates (TC) model was established. The prediction capability of the improved model was evaluated by finding the determination coefficient (R2), mean absolute error (MAE), and root‐mean‐square error (RMSE). Compared with the typical TC model, the prediction accuracy of the improved model was much higher. In addition, the relationships between the double T2 cut‐offs and fractal dimension (D) of the T2 spectrum of saturated artificial clayey soil were also identified.

Water Uptake of Polyelectrolyte Multilayers Including Water Condensation in Voids.

The paper addresses the swelling of polyelectrolyte multilayers (PEMs) at varying humidity. In particular, a new model will be presented, which takes the gradual filling of voids into account. Absorption of water results in PEM swelling. This absorbed water can be distinguished into swelling and void water. Swelling water leads to an increase in thickness and a change of the optical properties of PEMs, while the void water results only in a change of the optical properties. In former studies, neutron reflectometry was used to distinguish between swelling and void water. However, as we show in this study, it is possible to resolve the two different kinds of water in PEMs by ellipsometry, a much simpler tool. The present study evaluates and interprets the refractive index of polystyrenesulfonate/polydiallyldimethylammonium chloride (PSS/PDADMAC) PEMs. Both the swelling behavior and the refractive index change as a function of relative humidity and were found to be independent of the layer number. The void model and the extended void model were used to describe the data. The void model allows fitting the experimentally determined refractive index at humidity beyond 20% RH but fails for humidity lower than 20% RH. Therefore, we modified the existing model in order to account for air-water exchange. The extended void model assumes a gradual air-water exchange at low h and describes the refractive index over the entire humidity range in a precise way. Up to 30% RH, air and water coexist. Above this threshold, the voids are completely filled with water and this threshold does not change either with layer number or with the outermost layer. Furthermore, this model allows the determination of the volume fraction of the voids (0.05 ± 0.01) and the refractive index of the pure polymer matter (1.592 ± 0.002).

On the photodegradation of azithromycin, erythromycin and tylosin and their transformation products – A kinetic study

In this study, the photo-induced degradation of azithromycin (Azi), erythromycin (Ery) and tylosin (Tyl) was investigated. The three macrolides are regularly found in different kinds of water, and are thus considered a potential environmental risk. In search of efficient ways for elimination, the compounds were systematically irradiated with a polychromatic UVC light source emitting 185, 254 and discretely further up to 580nm. Due to their specific structural features, the macrolides possess different optical absorption characteristics leading to photodegradation pathways with dissimilar kinetic properties. Hence, the photodegradation products and their kinetics were analyzed using high-performance liquid chromatography (HPLC) coupled to high-resolution time-of-flight mass spectrometry. Among the degradants, i.e. the products formed during UV irradiation, both sugar moieties and lactone macrocycles were observed. Applying a first order kinetic model, the half-life of Azi was determined as 1.0−3.7min, that of Ery as 1.0−14.2min depending on the reaction conditions. The two compounds possess much lower absorption cross-sections than Tyl, in particular at 254nm. Their half-lives appeared at least three times higher than that of Tyl that has t1/2 of 0.2−1.0min. Based on quantum efficiency considerations, it was assumed that the degradation of Ery and Azi was mainly due to hydroxyl radical formation, which originated from water irradiation below 200nm, whereas Tyl experienced predominantly photo induced degradation. The photodegradants of Azi exhibited half-lives of over 200min, whereas most of the photo-products of Ery and Tyl showed half-lives of less than 10min. Photodegradation processes were investigated at pH 3, pH 7 and pH 9 and in the presence of hydrogen peroxide. Both the educts and the photo-products were degraded more rapidly under neutral and acid conditions.

Polyelectrolyte Complex Formation between Cationic Fixing Agent and Dissolved Substances in Papermaking

Dissolved substances (DS) in papermaking suspension contribute a large portion of negativity to the total dissolved and colloidal substances (DCS). Compared to colloidal substances (CS), dissolved substances are clearly more difficult to be removed by fixing agents (FA). Formation of polyelectrolyte complexes (PECs) between fixing agents and dissolved substances plays a very important role in clarifying the mechanism of a fixing agent acting on DCS. This study, therefore, focused on the characteristics of PECs formed between fixing agents and dissolved substances. Three polyamines (PA) with different molecular weight and slight different charge density were synthesized and used as fixing agents, in four different kinds of water including, two kinds of DCS water separated from a same deinked pulp (DIP) but with different size and distribution of CS particles, and two kinds of DS water modeled by oxidized starch (OS) and hemicelluloses (HC). The formation of PEC in these systems and their corresponding characteristics were characterized using focused beam reflectance meter (FBRM), laser particle size analyzer (LPSA), turbidity meter, and charge detection. From the results, it is concluded that for a given DS component and a certain kind of fixing agent, the formation of DSfixing agent PECs highly depended on the molecular weight of the fixing agent and its dosage. A fixing agent with enough low molecular weight could form big but loose and dispersible DS-FA PECs, increasing its dosage would produce denser and smaller PECs; and a fixing agent with enough high molecular weight could directly form dense PECs, increasing its dosage increased the size of PECs. Depositing DS-FA PECs onto small CS particles also played an important role in forming new CS particles with larger sizes, and in this case, a fixing agent with higher molecular weight tended to produce more large particles.