Polymer Dosage Research Articles

High-Temperature-Resistant, Low-Concentration Water-Controlling Composite Cross-Linked Polyacrylamide Weak Gel System Prepared from Oilfield Sewage.

The polyacrylamide weak gel is an effective system to block a high-permeability layer, realize water control, and enhance oil recovery. However, its application is limited by poor temperature resistance and high polymer dosage. In this paper, an inorganic–organic composite cross-linking agent was synthesized by using Cr(III) and phenolic resin. The composite cross-linking agent can cross-link low concentrations of polyacrylamide to obtain a high-temperature-resistant weak gel system in oilfield sewage. By adjusting the ratio of Cr(III), phenolic resin, and polyacrylamide, an optimum formula MF-7 can be obtained according to the gel strength. Results from evaluation experiments show that the strength of MF-7 can reach H grade even at polyacrylamide concentrations as low as 0.3%. The temperature resistance of the weak gel system is up to 100 °C, and no syneresis occurs after 330 h at 95 °C. Scanning electron microscopy (SEM) results show that MF-7 has a three-dimensional network structure with spherical nodes. The spherical node is composed of polyacrylamide, and its structure size is completely matched with the hydrodynamic radius of the used polyacrylamide. When combined with the network structure formed by Cr(III), the dense cross-linking network structure with nodes can greatly improve the strength and thermal stability of the gel system. The higher the molecular weight of the polyacrylamide used, the higher the strength of the gel obtained. Overall, the composite cross-linking agent can synergistically improve the mechanical properties of the gel, and this weak gel system formed by oilfield sewage is more economical and tolerant.

Preparation of Copolymer of 2-Methacryloyloxyethyldimethyl-3-sulfonic Acid Propylammonium Hydroxide and 3-(Methacryloyloxy) Propyltrimethoxysilane and Its Dye Adsorption Properties

While printing and dyeing bring us huge economic benefits, it also brings us huge challenges. Printing and dyeing will produce a large amount of wastewater, and the treatment of printing and dyeing wastewater has always been a concern. This work uses 2-methacryloxyethyl dimethyl-3-sulfonic acid propyl ammonium hydroxide, 3-(methacryloxy) propyl trimethoxysilane, and N, N’-methylene bispropylene as raw materials, and a photoinitiator is used to initiate polymerization under an ultraviolet lamp to prepare a copolymer gel. Taking the aqueous solution containing soap yellow as simulated dye wastewater, the adsorption performance of the prepared polymer for dyes was investigated. An ultraviolet spectrophotometer was used to investigate the effects of adsorption time, initial dye concentration, and polymer dosage on the adsorption performance. The performance test results show that the prepared polymer has high adsorption and removal efficiency for dyes containing soap yellow simulation, and has a potential application value.

Influence of polymer enhancement on water uptake, retention and barrier performance of geosynthetic clay liners

This paper explores the influence of polymer enhancement on water uptake and retention by geosynthetic clay liners (GCLs) across a wide suction range (up to 106 kPa), including the low suction regime (0.1–10 kPa) typically omitted in past studies. The suction measurement methods used enabled elucidation of water uptake and retention behaviour through the framework of GCL pore structures and their corresponding suction regimes. Polymer enhanced GCLs (PE-GCLs) have high maximum water uptake, and both the water entry and air expulsion values tend to be high. Due to high swelling, the onset of geotextile confinement for PE-GCLs was observed at high suctions. The impact of polymer becomes more apparent when the bentonite achieves a pseudo-two-layer interlayer hydration state at a suction of about 40 MPa (RH = 75%). The hydration mechanism for the polymer fraction in bentonite is unique to the specific polymer type, polymer dosage, and manufacturing process. The water retention behaviour at the low suction range is caused by the in-filling of geotextile pores, bentonite swelling and extrusion, and polymer water adsorption. Insights from this study can form the basis for developing a more suitable bimodal generalised model for fitting the water retention curves of GCLs.

Physiology in Talisia esculenta seedlings under irrigation with saline water on substrate with hydrogel

Salinity interferes in the physiology of seedlings from germination and seedling emergence, so it is necessary to adopt measures to mitigate its effects. The objectives of this research were to evaluate irrigation frequency, saline water, polymer, and container volume in the emergence and physiology of Talisia esculenta (A. St.-Hil.) Radlk. The treatments were obtained from the combination of polymer doses (0.0; 0.2; 0.6; 1.0; and 1.2 g dm-3), electrical conductivities of the irrigation water (0.3; 1, 1; 2.7; 4.3; and 5.0 dS m-1), and irrigation frequencies (daily and alternate), plus two additional treatments to assess the volume of the container. A randomized block design was used. Emergence and leaf indices of chlorophyll, fluorescence, and gas exchange were analyzed 100 days after sowing. The increase in electrical conductivity reduced and delayed seedling emergence. Decreasing irrigation frequency reduced the chlorophyll b index, stomatal conductance, transpiration, net CO2 assimilation, and carboxylation efficiency. The magnitude of the effects of electrical conductivity of water and polymer were associated with the frequency of irrigation. However, both salinity and polymer reduced practically all physiological variables. The reduction in container volume also affected the physiology of the seedlings, with more effects when irrigated on alternate days. The T. esculenta seedlings are considered sensitive to salinity, should be irrigated daily with water with less electrical conductivity than 1.0 dS m-1, as well as higher capacity containers used (0.75 vs 1.30 dm3).

Fluorination Promotes the Cytosolic Delivery of Genes, Proteins, and Peptides.

The cytosolic delivery of biomolecules such as genes, proteins, and peptides is of great importance for biotherapy but usually limited by multiple barriers during the process. Cell membrane with high hydrophobic character is one of the representative biological barriers for cytosolic delivery. The introduction of hydrophobic ligands such as aliphatic lipids onto materials or biomolecules could improve their membrane permeability. However, these ligands are lipophilic and tend to interact with the phospholipids in the membrane as well as serum proteins, which may hinder efficient intracellular delivery. To solve this issue, our research group proposed the use of fluorous ligands with both hydrophobicity and lipophobicity as ideal alternatives to aliphatic lipids to promote cytosolic delivery.In our first attempt, fluorous ligands were conjugated onto cationic polymers to increase their gene delivery efficacy. The fluorination dramatically increased the gene delivery performance at low polymer doses. In addition, the strategy greatly improved the serum tolerance of cationic polymers, which is critical for efficient gene delivery in vivo. Besides serum tolerance, mechanism studies revealed that fluorination increases multiple steps such as cellular uptake and endosomal escape. Fluorination also allowed the assembly of low-molecular-weight polymers and achieved highly efficient gene delivery with minimal material toxicity. The method showed robust efficiency for polymers, including linear polymers, branched polymers, dendrimers, bola amphiphilies, and dendronized polymers.Besides gene delivery, fluorinated polymers were also used for intracellular protein delivery via a coassembly strategy. For this purpose, two lead fluoropolymers were screened from a library of amphiphilic materials. The fluoropolymers are greatly superior to their nonfluorinated analogues conjugated with aliphatic lipids. The fluorous lipids are beneficial for polymer assembly and protein encapsulation, reduced protein denaturation, facilitated endocytosis, and decreased polymer toxicity compared to nonfluorinated lipids. The materials exhibited potent efficacy in therapeutic protein and peptide delivery to achieve cancer therapy and were able to fabricate a personalized nanovaccine for cancer immunotherapy. Finally, the fluorous lipids were directly conjugated to peptides via a disulfide bond for cytosolic peptide delivery. Fluorous lipids drive the assembly of cargo peptides into uniform nanoparticles with much improved proteolytic stability and promote their delivery into various types of cells. The delivery efficacy of this strategy is greatly superior to traditional techniques such as cell-penetrating peptides both in vitro and in vivo. Overall, the fluorination techniques provide efficient and promising strategies for the cytosolic delivery of biomolecules.

The impacts of high salinity and polymer properties on dewatering and structural characteristics of flocculated high-solids tailings

In seeking to better understand the inline flocculation technique for enhanced water recovery from concentrated fine-particle suspensions, polymers of different molecular weight (MW) and chemistry were used to treat a synthetic tailings slurry in a low-shear mixer for continuous flocculation under controlled conditions. The effects of dissolved salts in the slurry and polymer solution make-up water on dewatering performance were evaluated for conventional acrylamide/acrylate copolymers (BASF Magnafloc® products) and an alternative functional chemistry polymer (BASF Rheomax® DR 1050). The properties of the separated liquid and solid phases were examined to understand the impacts of salinity and polymer type on the formation of rapidly dewatering flocculated material. Higher concentrations of NaCl (0.006–0.6 M) and CaCl2 (0.006–0.06 M) salts in the unflocculated slurries formed larger coagulated structures, with focussed beam reflectance measurement (FBRM) showing greater pre-aggregation for the divalent salt. NaCl slurries show edge-to-edge (EE) and edge-to-face (EF) inter-particle associations that are open and easily disrupted while more compact face-to-face (FF) contacts are observed in CaCl2 slurries. For concentrated NaCl slurries, the dosing of medium-to-high MW polymers is generally preferred to maximise net water recovery, with the implication being that bridging mechanisms are still at play in high solids applications. In calcium-enriched slurries, the lower MW conventional copolymer gave comparatively better water returns than the other polymers when applied under low shear conditions, highlighting quite distinct aggregation processes compared to low solids flocculation. These results provide insight on the fundamental complexity of the ionic strength dependence of high solids-high dosage tailings flocculation, towards informing reagent polymer dosing and offering greater flexibility for end-of-pipe dewatering schemes.

Pickering Emulsions Stabilized by an Alkyl Chain-Bridged Lignin-Based Polymer without Additives and Organic Solvents.

In this article, an alkyl chain-bridged lignin polymer was prepared from our previous study. Then, an ultrafiltration method was used to classify the polymer into three fractions with a narrow molecular weight distribution. These three fractions were used to prepare novel Pickering emulsions without additives and organic solvents. The results show that the Pickering emulsion with fraction-3 of the highest molecular weight shows the best result compared with the other two fractions, and the Pickering emulsion is formed of droplets. The influence of oil-water ratios and fraction-3 dosages on the Pickering emulsions was also investigated in our study. The results show that the diameter of the droplets increases with increasing oil proportion and decreases with increasing lignin-based polymer dose. UV spectroscopy shows that the prepared Pickering emulsions have strong absorption properties from 300 to 800 nm, which will be expected to be applied in cosmetics, especially in sunscreen creams. Finally, the Pickering emulsion was also used to deliver ibuprofen, and the results showed that the embedding rate was as high as 10%. It is suggested that the Pickering emulsion stabilized by lignin-based polymers can be used for drug delivery. This will provide a potential research idea for high-value applications of lignin.

Evaluation of the use of a HiMA binder to extend the durability of porous friction courses (PFC)

ABSTRACT Porous friction courses (PFC) are thin layers of asphalt mixtures with open gradations and high air void contents, which are placed over conventional flexible pavements. Although they improve various safety and environmental issues, their main difficulty is their short service life. A common practice to enhance PFC durability is the use of modified asphalt binders (e.g. regular polymer-modified asphalt (PMA) or asphalt rubber). However, this approach has not been enough to achieve life-spans close or equal to those of dense-graded hot mix asphalt. The use of highly polymer-modified asphalts (HiMA), which are binders modified at polymer doses near 7–8% by total weight of the binder, constitutes an alternative to overcome this challenge. This work evaluates the mechanical performance of four PFC mixtures fabricated with a regular polymer modified (PMA) and a HiMA binder, and two aggregate sources. The experimental plan included the semicircular bending (SCB), IDEAL-CT, Cantabro abrasion loss and Tensile Strength Ratio (TSR) tests at intermediate temperatures and various ageing conditions. Results indicate an enhanced cracking and degradation resistance for PFC mixtures containing HiMA and suggest that the use of this type of asphalt binder could increase the service life of these mixtures.

INCREASE IN THE EFFICIENCY OF WATER SHUT-OFF WITH THE APPLICATION OF POLYETYLENPOLYAMINE ADDED CEMENT

As a result of intrastratal and interlayer flows of produced water of varying intensity, 25% of oil and gas wells are water-encroached in the world. Due to behind casing flow during the operation of oil and gas wells generally reduces the field's development efficiency. In the study, 1-6% (weight) polyethylene polyamine (PEPA) was added to the water in which the cement mixture will be prepared. The temperature dependence of the beginning and the end of the setting time of the obtained cement mortar was determined. Also, the adhesion properties of the cement mortar, the dependence of the strength to bending and compression on the dose of polymer were examined. It found that cement stone made of mixing cement with an aqueous solution containing 1-4% PEPA had high elastic properties. In addition, the presence of 2±1.5% PEPA in the specified amount of tampon solution increases the strength and to depressions of cement stone, improves adhesion properties.

ПРИЖИВАЕМОСТЬ И РОСТ СОСНЫ ОБЫКНОВЕННОЙ В УСЛОВИЯХ ПРИМЕНЕНИЯ ПОЛИМЕРОВ ДЛЯ УСЛОВИЙ СТЕПИ И ЛЕСОСТЕПИ

The article presents the results of a study of the survival, growth and condition of forest crops of scots pine with the use of polyacrylamide polymer "AQUASORB". The object of research was the forest cultures of scots pine in the conditions of the steppe on sand and sandy soils, in the conditions of the forest-steppe - on loam. The polymer was used as a gel in doses of 125 ml and 250 ml, and also in dry form was introduced into the root system of seedlings before planting. The ability of the polymer to absorb water and give it to plants with its subsequent shortage in the soil caused its effectiveness, which is confirmed by an increase in the survival rate of pine crops by 16-20% in steppe conditions on sand and sandy soils and by 9-13% on loam in forest-steppe conditions. The intensity of pine growth in variants with different doses of polymer increased by 48-78% in steppe conditions and by 36-60% in forest-steppe conditions in the first year of pine crops' life. In the third and fifth years of the life of pine crops, the intensity of pine growth in (150) variants with polymer decreases, which indicates the leveling of the polymer's action in the soil over time. Positively affecting the survival rate and growth rate of pine crops, AQUASORB polymer contributes to an increase in the preservation of pine forest crops in the fifth year of life by 1.2-1.3 times. The effectiveness of the polymer decreases with sufficient water reserves in the soil.

Process optimization & reactive extrusion of high-molecular weight Poly(butylene-adipate-co-terephthalate) (PBAT) polymer for film blowing application

The present study demonstrates a novel approach of the process optimization for the synthesis of Poly(butylene-adipate-co-terephthalate) polymer, and its exclusive reactive extrusion for the film blowing application. The polymers have been synthesized under different processing conditions in order to determine the effect of different variables on the kinetics and optimize the system to obtain biopolymers. The catalytic chemistry of tetra-isopropyl titanate (TIPT) and zinc acetate in the optimal dosage resulted in the development of very high molecular weight PBAT, which is very essential for a polymer to have superior mechanical properties. The polymers were characterized using gel permeation chromatography (GPC), FT-IR, and calorimetry (DSC) analysis to investigate their properties. Furthermore, the polymer compounding was conducted using a unique reactive extrusion process which resulted in the compound with physiochemical property retention at the reduced polymer dosage level. This novel extrusion process reduced the polymer consumption in the compounding by up to 25% with intact properties. Mechanical and thermal properties were enhanced using metal complex-based inorganic coupling agents and fluoropolymers during the process. In the blowing, a flexible and thin film of uniform thickness was obtained in the continual run on the machine. The films were tested for mechanical properties which were at par with commercially available bags. With the ever-increasing demand for environmental-friendly products in plastics & polymers and stricter regulations against the use against conventional plastics, these polymer-based bio-films can be extensively used in the packaging and plastic bag applications due to their biodegradability and the superior strength in terms of mechanical properties which are comparable to the one exhibited by conventional polyethylene bags.

Design and synthesis of a new magnetic molecularly imprinted polymer nanocomposite for specific adsorption and separation of diazinon insecticides from aqueous media

Today, molecularly imprinted polymers have received much engrossment as selective adsorbents and substrates. In the present study, a magnetic molecularly imprinted polymer (MIP) based on clay, graphene oxide and polydopamine was synthesized and used for adsorption and specific entrapment of Diazinon pesticide. The magnetic MIP nanocomposite was characterized by XRD, FT-IR, SEM, VSM, and AFM methods. The response surface method (RSM) was used to optimize and modeling the effective parameters of the adsorption of Diazinon by this polymer, and the results were compared with an artificial neural network (ANN). The results showed magnetic saturation of GO/Clay/Fe3O4@PDA MIP nanocomposite is equal to 8.28 emu/g, average particle size, average surface roughness and imprinting factor of this polymer are equal to 105 nm, 66.72 nm and 2.35, respectively. This polymer has a very selective ability to adsorption of Diazinon by removal percentage equal to 99.85 at pH = 7, the concentration of Diazinon = 1.45 ppm, the dosage of polymer = 1.24 g/L, time = 16 min. Also, the RSM results showed that the model included the effect of parameters on the absorption efficiency is a quadratic polynomial equation with the coefficient of determination equal to 0.98% and the most effective parameter on removal percentage is the dosage of the polymer. The artificial neural network with 11 neurons in the hidden layer with the coefficient of determination of 0.96% was also suitable for modeling the absorption process. Compared to the ANN model, the RSM model has better capability and lower error values. Freundlich isothermal models and pseudo-second-order and Elovich kinetic models in different concentrations of Diazinon were appropriate for explanation the adsorption process. The mechanism of Diazinon adsorption by MIP nanocomposite was influenced by intraparticle and extraparticle diffusion. Also, GO/Clay/Fe3O4@PDA MIP nanocomposite has an adsorption capacity of more than 98% up to nine cycles of the adsorption/desorption process.

Optimizing the recovery process of ceramic grade calcium fluoride from hydrofluoric/hexafluorosilicic acid wastewater

Chemical precipitation using calcium salts has been widely applied in hydrofluoric acid wastewater treatment due to its simplicity, flexibility and economy. Coagulants/flocculants are used to improve solid-liquid separation in a fine precipitate of calcium fluoride (CaF2). As a result, a large amount of sludge is generated by CaF2 precipitation process. In order to move towards a circular economy, the current study developed an environment-friendly and cost-effective approach to treat concentrated hydrofluoric/hexafluorosilicic acid wastewater (∼117 g F−/L) obtained from an optoelectronic industry in Taiwan and to recover fluoride as the high purity CaF2, as well as to reduce the amount of final waste disposal. The influence of three independent variables, including calcium-to-fluoride molar ratio ([Ca2+/F−], silicon concentration ([Si4+]), and polymer dosage applied, on the purity of recovered CaF2 products, was investigated and optimized by combining response surface methodology (RSM) with central composite design (CCD). The ceramic grade CaF2 of 85.6–87.9% was achieved under the optimum conditions as [Ca2+/F−] of 0.618–0.645, [Si4+] of 1.48 g/L, and polymer concentration of 17.2–17.8 mg/L. The final turbidity, residual fluoride concentration in the supernatants and fluoride removal efficiency were 14.8–16.2 NTU, 62.2–67.6 mg/L and greater than 99%, respectively. The value of R2 = 0.9498 and adjusted R2 = 0.9319 indicated an adequate correlation between experimental results and predictions by the quadratic model. In addition, a new insight into the CaF2 purification method has been proposed based on the idea of pH control.

Enhanced removal of per- and polyfluoroalkyl substances in complex matrices by polyDADMAC-coated regenerable granular activated carbon

Granular activated carbon (GAC) has been used to remove per- and polyfluoroalkyl substances (PFASs) from industrial or AFFF-impacted waters, but its effectiveness can be low because adsorption of short-chained PFASs is ineffective and its sites are exhausted rapidly by co-contaminants. To increase adsorption of anionic PFASs on GAC by electrostatic attractions, we modified GAC's surface with the cationic polymer poly diallyldimethylammonium chloride (polyDADMAC) and tested its capacity in complex water matrices containing dissolved salts and humic acid. Amending with concentrations of polyDADMAC as low as 0.00025% enhanced GAC's adsorption capacity for PFASs, even in the presence of competing ions. This suggests that electrostatic interactions with polyDADMAC's quaternary ammonium functional groups helped bind organic and inorganic ions as well as the headgroup of short-chain PFASs, allowing more overall PFAS removal by GAC. Evaluating the effect of polymer dose is important because excessive addition can block pores and reduce overall PFAS removal rather than increase it. To decrease the waste associated with this adsorption strategy by making the adsorbent viable for more than one saturation cycle, a regeneration method is proposed which uses low-power ultrasound to enhance the desorption of PFASs from the polyDADMAC-GAC with minimum disruption to the adsorbent's structure. Re-modification with the polymer after sonication resulted in a negligible decrease in the sorbent's capacity over four saturation rounds. These results support consideration of polyDADMAC-modified GAC as an effective regenerable adsorbent for ex-situ concentration step of both short and long-chain PFASs from real waters with high concentrations of competing ions and low PFAS loads.

Development and Characterization of Silver Containing Free Standing Polymer FILMS for Dosimetry Applications.

Polymer gels and films, due to their near equivalence to biological tissue, are amongst the most promising future dosimetry tools for medical applications. The application of polymer dose gels is limited by the sensitivity of dose readout methods and dose gel properties. It is a challenge to find suitable dosimeters for registration of doses delivered to the target by orthovoltage therapy units. The application of metal-particle-enriched polymer composites for dose registration in X-ray therapy might be an elegant solution, especially if recent dose-reading technologies exploring advantages of different physical phenomena are involved. In this work, X-rays from the orthovoltage therapy range were used for the irradiation of experimental samples. In addition, radiation-induced processes of formation of silver nanoparticles in AgNO3–PVA gels and in free standing AgNO3PVA films, also containing some additional solvents, namely glycerol, ethanol, and isopropanol, have been investigated, with the aim to apply the developed composites for medical dosimetry purposes. A simple and environmentally friendly method for the formation of free-standing AgPVA films at room temperature was proposed and realized for preparing AgPVA films for investigation. Radiation-induced synthesis of silver nanoparticles in AgPVA composites was investigated, analyzing LPSR-based UV-VIS spectral changes to the irradiated films with respect to irradiation doses, and dose-related tendencies were also evaluated. It was shown that AgPVA films were more sensitive for detection of doses from the interval 0–1.0 Gy, thus indicating potential application of AgPVA films for dosimetry purposes.

Effects of different polymerisation conditions using hybrid polymer on high turbidity suspensions

PurposeIn this study, new hybrid polymers composed of Zinc chloride (ZnCl2), acrylamide and chitosan were prepared at different ratios and temperatures. The effects of pH and polymer dosage were examined for different polymers to observe their efficiency in the removal of turbid water. The polymers’ zeta potential, morphology, elemental composition and functional groups were also identified and studied.Design/methodology/approachThe free-radical polymerisation process was executed in the presence of N, N’-Methylene bis-acrylamide and potassium persulphate in one molar acrylamide solution. ZnCl2 and chitosan (CO) were later introduced into the suspension under nitrogen gas flow. Ratio and temperature were varied during polymerisation. The hybrid polymer produced, termed Polyacrylamide + chitosan oligosaccharide + zinc chloride (PAMCOZ), was analysed using Fourier transform infra-red spectroscopy attenuated total reflectance and scanning electron microscope with energy dispersive X-ray. The hybrid PAMCOZ was experimented with in high turbid kaolin suspension using jar testing analysis to see its ability as a coagulant.FindingsThe coagulation process using PAMCOZ with a ratio of 11 (3:2) at 70°C surrounding temperature showed a 100% reduction at pH 4 with 50 mg/L of the polymer. The functional groups present in ratio 11 polymer were hydroxyl, carbonyl, amide and methyl groups. In addition, several elements were spotted on the surface of PAMCOZ, such as zinc (Zn), carbon (C), chlorine (Cl), nitrogen (N) and oxygen (O). The effect of pH also demonstrated that PAMCOZ was unfavourable in an alkaline turbid water environment.Research limitations/implicationsDue to the research methodology approach, the research results may lack actual wastewater application. Therefore, researchers are encouraged to test the hybrid coagulant on raw wastewater, such as pulp and paper mill effluent with a high turbidity value similar to this study.Originality/valueThe polymerisation between zinc chloride, acrylamide and chitosan has not yet been applied. The different ratios and effects of temperature were analysed on PAMCOZ to see the turbidity removal. PAMCOZ showed better turbidity removal in acidic conditions.

Investigation on the turbidity reduction from wastewater using electroflocculation process and aerobic mixed microbial culture: Modelling and pathway analysis

Contamination of natural water resources by industrial activites is a serious problem that appears in worldwide. The key purpose of the work is to explore the treatment of food wastewater using aerobic mixed microbial culture (AMC) and electroflocculation (EF) process. Box-Behnken design (BBD) incorporated in Response surface methodology (RSM) was used to analysis and model the each process. The effects of inoculum concentration (IC), mixing intensity and temperature has been examined over the turbidity reduction (Y1) in AMC process; where as current density, pH, treatment time and polymer (Polyethyleneimine) dose has been examined over the turbidity reduction (Y2) in EF process. The response models developed explained >97% variability for turbidity reduction. The numerical optimization was used to find out the optimal setting and both the process significantly reduce the >70% of turbidity. UV/Vis spectrophometer confirms the efficiency of each process for turbidity reduction. The operating cost of AMC and EF found to be 1.08 US $/m3 and 4.55 US $/m3, respectively were detemined in optimal conditions. 95% of organic matters was found in sediment of AMC which can be used as outstanding organic fertilizer.

The separation of kreutzonit particles by cationic pullulan derivatives from model suspension

In the present work the flocculation properties of some cationic derivatives based on pullulan have been tested in a synthetic suspension of zirconium silicate (kreutzonit). The flocculants contain either quaternary ammonium salt groups (grafted chains, poly[(3-acrylamidopropyl)-trimethylammonium chloride] onto the pullulan (P-g-pAPTAC)) or tertiary amine groups (3-dimethylamino-1-propylamine-pullulan) (DMAPAX-P). The impact of polymer dose, the charge content and type (tertiary amine or quaternary ammonium salt groups), the grafted chains length and the suspension pH on the flocculation efficiency have been taken into consideration. The separation of mixtures consisting of kreutzonit, K-feldspar, kaolin, hematite (Fe2O3) particles by some of the above mentioned cationic derivatives was also followed. The addition of different doses of pullulan derivatives to kreutzonit dispersion as well as to particles mixture led to the increase of particles removal efficiency up to 95–99% in the optimum dose intervals. The charge patch and bridging mechanisms played an important role in the flocculation process, as revealed by zeta potential measurements. Flocs resulting from the flocculation process have been used successfully in removal of fungicide Bordeaux mixture particles from synthetic wastewater; a removal efficiency higher than 95% has been found for the optimum amount of flocs (10 g flocs per liter of fungicide suspension).

Revealing channel controlled nutrient release mechanism of bio-oil polymer coated controlled-release fertilizer

Nutrient channel release mechanism of bio-oil polymer coated controlled-release fertilizer (BCRF) was revealed. The bio-oil polymer was developed by co-polymerization of castor oil and epoxy soybean oil for the preparation the coating layer of the BCRF. Scanning electron microscopy (SEM) technology was introduced to investigate the channels in the coating layer of the BCRF and their effect on the nutrient release. Three types of channels affected the nutrient release rate of BCRF. The longevity of the BCRF increased due to decreasing nutrient release channels as the dosage of the bio-oil polymer increased. The number, length and tortuosity of the channels were decisive for the nutrient release rate of BCRF, while moisture, temperature and coating technology were sufficient factors. Higher the ratio of bio-oil polymer resulted in an increasing number and the cross-sectional area of channels in the coating layer. The dosage and ratio of the bio-oil polymer had no effect on the surface structure of the BCRF before culture. The small channel was 48.9 times that of the large channels, but cross-section area of the large channels was 79.9 times that of small channels. The large channels played a decisive role in controlling nutrient release rate of BCRF. The quantitative information of BCRF nutrient release rate depended on adjusting the amount of coating material, the ratio of bio-oil polymer in the material, coating technology and channel-forming agents. When the ratio of bio-oil polymer to polyisocyanate was 5:4–5:5 and the amount of coating material was at least 3 % of the weight of the core fertilizer, the BCRF exhibited excellent controlled release performance. The experiment will help the production of environmentally friendly controlled-release fertilizers through the application of bio-oils to adjust nutrient release performance and reduce fertilizer pollution in agricultural production.

A novel hyper-cross-linked polymer for high-efficient fluid-loss control in oil-based drilling fluids

In order to control filtrate at high-temperature and high-pressure condition in oil-based drilling fluid for drilling process of oil and gas wells, an amine cross-linked polymeric fluid-loss-control material (ACP) was designed and synthesized. This material was synthesized through cross-linking poly (maleic anhydride- alt -1-octadecene) (PMAO) with amine. The structure of hyper-cross-linked copolymer enables the ACP polymers to withstand higher aging temperatures and less affect the rheology of oil-based drilling fluid. The structures of ACP polymers we synthesized were confirmed by FT-IR spectra and elemental analysis. TGA results showed that the decomposition temperature of ACP polymers exceeds 400 °C. And the amphiphilic nature of ACP polymers makes them enhance the stability of water-in-oil emulsion of oil-based drilling fluid. In addition, combining the viscoelasticity data of amine cross-linked PMAO suspensions and the fluid-loss control performance of ACP in oil-based drilling fluid, it was found that the increase of amino number in the cross-linker can effectively reduce the filtrate permeating, which is because the aggregation of hydrophilic amino makes ACP polymer form a dense structure to prevent oil from passing through. After screening of ACP polymers, the preferred one (ACP-5) can reduced filtrate volume of oil-based drilling fluid by over 90% with small dosage (3 g in 400 mL drilling fluid) after hot rolling for 16 h at 232 °C. • A series of novel amine cross-linked ACP polymers were prepared. • ACP polymers are resistant to high temperature and high pressure condition. • Emulsion stability of oil-based drilling fluid increases with ACP polymers added. • Fluid loss was efficiently reduced with a small dosage of ACP polymers.