Development of Bench-Scale Direct Contact Membrane Distillation System for Treatment of Palm Oil Mill Effluent

The oil palm industries generate large amounts of effluent that can cause pollution and, as a result, pose serious threats to the environment. Recently, membrane distillation (MD) has been identified as a potential candidate for treatment of palm oil mill effluents (POME). This is because the release of POME at high temperature may reduce the need to preheat the effluent prior to operation. The objective of this article is to manufacture a bench-scale MD system and assess the performance of the system in POME treatment. This project started with the design of a process and instrumentation diagram (P&ID) and continued with the fabrication part. Subsequently, the performance of the direct contact membrane distillation (DCMD) system was tested using POME as a feed solution. Three different feed temperatures (55 °C, 65 °C and 75 °C) were analyzed during the testing. The results obtained show that the permeate flux increased with the increase of feed temperature with the highest flux is 10.76 kg/m2.hr. More than 85% of pollutants including ammonia nitrogen, color, chemical oxygen demand (COD) and turbidity were rejected. This shows that the system is capable of treating POME and producing high quality permeate water

Human Treated Dentin Matrix Hydrogel as a Drug Delivery Scaffold for Regenerative Endodontics

Introduction: The objective of the current study was to develop a human treated dentin matrix (hTDM) hydrogel for use as a scaffold to allow the controlled release of an antimicrobial agent for regenerative endodontics. Materials and Methods: Human extracted teeth were treated via chemical demineralization using ethylene diamine tetra-acetic acid solution to produce hTDM powder. Fourier transform infrared spectroscopy (FTIR) was conducted to determine the functional groups of hTDM, scanning electron microscopy (SEM) was used to define the morphology/particle size of hTDM, and energy dispersive X-ray analysis was performed to identify the superficial apatite groups. Prepared hTDM powder was added to the amoxicillin-clavulanate mixture with a mass ratio of 1:1. Then, the combination was dripped into a 5% (w/v) calcium chloride solution. Antibiotic release profiles were evaluated for 14 days via high performance liquid chromatography (HPLC). Hydrogel degradation properties were studied for 14 days using 10 mL of phosphate buffered saline (PBS). Encapsulation efficiency was determined by HPLC, while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of amoxicillin-clavulanate were determined against Enterococcus faecalis (E. faecalis). The antibacterial activity of amoxicillin-clavulanate against E. faecalis was investigated for 14 days via agar diffusion test. Statistical analysis was performed with the Shapiro-Wilk test (P=0.05). Results: hTDM showed statistically a significant difference for percentage weight change (P=0.1). The encapsulation efficiencies for hTDM hydrogel with antibiotic and hydrogel with antibiotic was 96.08%±0.02 and 94.62%±0.11, respectively. MIC and MBC values of amoxicillin-clavulanate against E. faecalis were 2.4 µg/mL and 9.6 µg/mL, respectively. The antibacterial activity of antibiotic loaded hTDM hydrogels was significantly greater than loaded hydrogels alone by 31% after 4 and 100% at 14 days, respectively (P≤0.001). Conclusions: This in vitro study showed antibiotic-loaded injectable hTDM hydrogel could be an alternative system to transfer antibiotic-based intracanal medicaments for use in regenerative endodontics

Radial Distribution Function Analysis of the Polyamide Thin Film Composite formation using Trimesoyl Chloride and Piperazine

Polyamide thin film composite (TFC) membranes are well known for their performance and strength which normally applied in pervaporation dehydration and reverse osmosis field. TFC is produced by the rapid reaction between aqueous and organic monomer. However, the interaction between monomers is not well discussed at the atomic level and there is no precise tool to measure the effectiveness of the selection of organic with the aqueous monomer to form a stable TFC layer. Thus, this paper aims to analyze the interaction between aqueous monomer and organic monomer using the Molecular Dynamic (MD) simulation to form the TFC membrane. This work was done by using Piperazine (PIP) as the aqueous monomer with the combination of Trimesoyl Chloride (TMC) as the organic monomer in the binary systems. The simulation involved the setting of Ewald Summation Method, COMPASS force field, equilibrium phase by microcanonical, NVE (constant volumes and total energy) and run-production stage by NPT (constant pressure and temperature). Analysis by the Radial distribution function (RDF) explicates the intermolecular interfacial of 5.75 Å between the bonding of N (Amine) - C (TMC) atoms at the distance of 1.0 Å. This study suggested that the TFC formed by the interaction between TMC - PIP is very much stable based on the higher interaction in a very short distance

Recent advances in solar drying system: A review

Research on solar dryer technology proliferates since it reduces the drying period while keeping nutritional values in the agricultural products. This paper presented a review of recent advances in the solar drying system. This review is composed of working principles and classifications of solar dryers. They were classified into two main elements: airflow modes, either passive or active, and the way heat is transferred: direct, indirect, mixed-mode, and hybrid. The hybrid system used several types of elements to supply additional heat in the drying system, as elaborated in this paper, such as the electrical heater, biomass, and photovoltaic system. The advantages and disadvantages of the solar dryer also being discussed in this pape

Non-invasive measurement of cholesterol in human blood by impedance technique: an investigation by 2D finite element field modelling

This paper concerns detection of solid particles suspended in conductive media by impedance technique. The technique is based on changes in impedance measured between two electrodes placed across a given volume of conducting medium. It presents a methodology for modelling and investigation of the feasibility of such a technique for particle detection by 2D finite element (FE) field modelling. This is based on modelling and computation of electric field distribution between the above electrodes. It establishes the modelling approach, the complexity involved and justifies the need for modelling in 3D to incorporate some of the effects that cannot be taken into account in 2D models. It reports on the modelling investigation for a specific case of detecting, by impedance technique cholesterol particles suspended in human blood and points to a possible instrument for non-invasive measurement of blood cholesterol level

Historical atmospheric pollution trends in Southeast Asia inferred from lake sediment records

Fossil fuel combustion leads to increased levels of air pollution, which negatively affects human health as well as the environment. Documented data for Southeast Asia (SEA) show a strong increase in fossil fuel consumption since 1980, but information on coal and oil combustion before 1980 is not widely available. Spheroidal carbonaceous particles (SCPs) and heavy metals, such as mercury (Hg), are emitted as by-products of fossil fuel combustion and may accumulate in sediments following atmospheric fallout. Here we use sediment SCP and Hg records from several freshwater lentic ecosystems in SEA (Malaysia, Philippines, Singapore) to reconstruct long-term, region-wide variations in levels of these two key atmospheric pollution indicators. The age-depth models of Philippine sediment cores do not reach back far enough to date first SCP presence, but single SCP occurrences are first observed between 1925 and 1950 for a Malaysian site. Increasing SCP flux is observed at our sites from 1960 onward, although individual sites show minor differences in trends. SCP fluxes show a general decline after 2000 at each of our study sites. While the records show broadly similar temporal trends across SEA, absolute SCP fluxes differ between sites, with a record from Malaysia showing SCP fluxes that are two orders of magnitude lower than records from the Philippines. Similar trends in records from China and Japan represent the emergence of atmospheric pollution as a broadly-based inter-region environmental problem during the 20th century. Hg fluxes were relatively stable from the second half of the 20th century onward. As catchment soils are also contaminated with atmospheric Hg, future soil erosion can be expected to lead to enhanced Hg flux into surface waters

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Effect of pH of Wastewater on Turbidity Reduction using Jackfruit Peel (Artocarpus heterophyllus) Coagulant

Presently, wastewater treatment using chemical coagulants has been major concern due to production of sludge in large volume, high costs and health effects. Thus, the use of plant-based coagulants has attracted researchers to overcome these problems. This study describes the effect of pH on coagulation process by using of jackfruit (Artocarpus heterophyllus) peel as coagulant. The coagulant from jackfruit peel was prepared by extraction method using distilled water. Synthetic sewage was used in this study to imitate medium strength domestic wastewater. Jar test experiment was carried out and the pH of wastewater was varied using hydrochloric acid and sodium hydroxide. After treated, the turbidity of the wastewater was measured to determine the percentage of reduction. The coagulant extracts were characterized using FTIR and zeta potential. It was observed that the jackfruit peel extract works the best as a coagulant at pH 2. Jackfruit peel coagulant can be used as primary treatment of the wastewater and believed to be an environmental friendly alternative

Study on the zeta potential effect of Artocarpus heterophyllus natural-based coagulant in wastewater treatment

The application of chemical coagulants which is damaging to environment and human health has triggered to the exploration of new coagulants from natural based sources. This study emphasized on the performance of a treatment process to remove particles in the synthetic domestic wastewater by coagulation using Artocarpus heterophyllus (jackfruit) peel extract and evaluation of zeta potential (ζ). The measurement of zeta potential which is the criteria defining the electrostatic interaction between pollutants and natural coagulant agent is used in proposing mechanism of coagulation. The jar test experiment was carried out and the treated wastewater was analysed to determine reduction in turbidity, BOD, COD and TSS. The coagulant extracts were characterized in terms of surface charge. The best operating conditions were: pH 2 and dosage 60 mg/L. The corresponding removal efficiencies for turbidity, TSS, COD and BOD were 80 %, 70 %, 46 % and 20 % respectively. The measured zeta potential of the coagulant was -25.2 mV at its original pH, 6.95. On the other hand, the surface charge of synthetic wastewater was positive at pH 2 and later turned to be negative as the pH is increased up to pH 12. This best describes that jackfruit peel coagulant possessed the characteristic of anionic polyelectrolytes which involves bridging mechanism. The results obtained here suggest that coagulation using Artocarpus heterophyllus peel extract can be employed as an effective and low-cost preliminary technique in wastewater treatment process

PVDF-CLOISITE hollow fiber membrane for CO2 absorption via membrane contactor

The effect of cloisite concentrations on CO2 absorption via polyvinylidene fluoride-cloisite hollow fiber in membrane contactor system was investigated. PVDF polymer was modified by introducing different compositions of cloisite clay (S1: 0%, S2:1 wt%, S3: 3 wt% and S4: 5 wt%) into the polymer solution. The hollow fiber membranes were examined via liquid entry pressure (LEPw), contact angle and scanning electron microscope (SEM). CO2 absorption test was conducted at different liquid absorbent flow rates of 1M MEA. S4 gives highest Liquid entry pressure value and S3 obtained highest contact angle value at around 87.21º. Different concentrations of cloisite exhibited various finger-like structure with sponge-like morphology on the membrane lumen side. Meanwhile, the highest CO2 absorption flux of 3.41×10-2 mol/m2.s at flowrate of 200 ml/min was obtained for membrane S4. Long term performance for membrane S4 up to 55 hours of CO2 absorption showed increasing absorption trend up to 6.78 ×10-2 mol/m2.s of CO2 fluxes