Evaluation Of Parameters Governing The Release Rate Of Phosphate Ions From Chitosan-Coated Phosphorus Fertilizer Pellets

Coated fertilizers, which belong to the group of controlled-release fertilizer (CRF) have been widely used in agricultural field in order to reduce the ground water pollution and at the same time increase the nutrient use efficiency by crops. Chitosan is one of promising biopolymers that can be used as a coating material in order to control the release rate of nutrients from fertilizer pellets due to its excellent properties. Most of the previous studies based on the chitosan coating were focused on the urea and compound fertilizers of nitrogen-phosphorus-potassium (NPK). Studies regarding the chitosan-coated phosphorus fertilizers have not been addressed so far. Furthermore, previous studies also neglected the evaluation of parameters that govern the nutrient release rate using the mechanistic model. Understanding the transport parameters such as diffusion coefficient of nutrient through coated pellet is very important in order to improve the design of fertilizers. This study is mainly focused on investigating the release rate of phosphate ions from the chitosan-coated phosphorus fertilizer pellets and evaluation of parameters that controlled the nutrient release using mechanistic model. Appropriate experiments were carried out in order to determine the phosphate ions release rate from pellets with different number of chitosan coating layers (one, two and three layers) under variation of pH conditions (pH 5.7, 7.1 and 8.5). Experiments were also conducted for short and long period of release tests

Interfacial Enhancement Of Mixed Matrix Membrane Using Ionic Liquid For Co2 Separation

The use of mixed matrix membrane (MMM) appears to be a promising approach in CO2 separation application due to the synergistic effects of polymer and inorganic materials. However, poor compatibility between inorganic particles and polymer often results in interfacial defects that reduce the MMM gas separation performance. In this study, asymmetric MMMs comprises of polysulfone (PSf) and SAPO-34 zeolite were fabricated via dry-wet phase inversion. The loading of SAPO-34 zeolite in the MMM formulation was first varied from 5 to 15 wt.% to study the effect of zeolite loading to the characteristics of the MMMs and CO2 gas separation performance. Increasing the zeolite loading has enhanced the CO2 permeance of the MMM but reduced the CO2/N2 selectivity as compared to the neat PSf membrane. The incorporation of SAPO-34 zeolite in the PSf membrane has resulted in the voids formation at the polymer/filler interface contact as shown by scanning electron microscopy images. Ionic liquid (IL) which selective towards CO2 was used in this study to modify the MMM by sealing the interface defects in the membrane. Two different approaches namely premodification and post-modification were applied in the MMM modification. Results showed that the post-modification method with IL has improved both polymer/zeolite interface contact and gas separation performance of the MMM as compared to the premodification approach. The post-modification method was further explored by studying the effects of IL concentration, zeolite loading, solvent and IL properties. It was found that the post-modification of the MMM incorporated with 5 wt. % zeolite loading has enhanced the CO2/N2 selectivity about 820 % over the unmodified MMM by increasing the concentration of the IL/ethanol solution from 0.2 to 0.4 M. The CO2/N2 selectivity can also be increased when more polar solvent such as methanol was used in the post-modification of MMM involving low IL concentration (0.2 M). The CO2 permeance and CO2/N2 selectivity of IL-modified MMM was improved to 4.93-7.19 GPU and 26.63-35.21 respectively by using IL with large molecular weight since the reduction in zeolite porosity could be minimized. Analysis of the gas transport parameters revealed that the incorporation of IL into the MMM has increased the CO2 solubility of the membrane but the improvement in the CO2/N2 selectivity was mainly contributed by the diffusivity selectivity. The gas separation performance for the IL-modified MMM was observed to sustain when being exposed to the humid gas condition. Thus, the post-modification approach of MMM using IL can be as an alternative strategy in membrane development for CO2 separation application

In-Vitro Apatite Growth On Porous Â-Tricalcium Phoshpate Scaffolds Coated With PHVB

The bioactive properties of polyhydroxybutyrate-co-valerate (PHBV) coated beta-tricalcium phosphate (β-TCP) have been studied invitro. Porous β-TCP scaffolds have been prepared using a template method and sintered at 1450 °C.The bio ceramics were then coated with PHBV solution before being immersed for 6 weeks in a simulated body fluid (SBF)at 37°C.At the end of the immersion time, insignificant changes in the SBF pH value was observed, suggesting good stability against hydrolytic degradation. X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analyses revealed the presence of apatite.Morphological analysis by SEM showed the formation of apatite crystals in the form of flakes and globular deposits on the scaffold surface.This bonelike apatite indicates good biological activity of the bio ceramics scaffold with PHVB coating suggesting that the composite has potential for bone tissue engineering applications

An Overview of the Modification Strategies in Developing Antifouling Nanofiltration Membranes

Freshwater deficiency has become a significant issue affecting many nations’ social and economic development because of the fast-growing demand for water resources. Nanofiltration (NF) is one of the promising technologies for water reclamation application, particularly in desalination, water, and wastewater treatment fields. Nevertheless, membrane fouling remains a significant concern since it can reduce the NF membrane performance and increase operating expenses. Consequently, numerous studies have focused on improving the NF membrane’s resistance to fouling. This review highlights the recent progress in NF modification strategies using three types of antifouling modifiers, i.e., nanoparticles, polymers, and composite polymer/nanoparticles. The correlation between antifouling performance and membrane properties such as hydrophilicity, surface chemistry, surface charge, and morphology are discussed. The challenges and perspectives regarding antifouling modifiers and modification strategies conclude this review