Physical Cleaning Research Articles

1-(3-Aminopropyl) imidazole (APIm) modified ultrafiltration (UF) membrane for mitigating alginate fouling caused by calcium

UF is widely used as a wastewater treatment and recycling technology. However, membrane fouling is still an important factor affecting the wide application. In this study, APIm with positive amino group was adsorbed to the surface of the carboxylated polyacrylonitrile (PAN) membrane by electrostatic force to reduce the fouling of sodium alginate (SA) caused by Ca2+. The results show that 1 v/v% APIm was selected as the optimal dosage, accompanied by the highest water flux of 330.5 L·m-2h−1 bar−1 and bovine serum albumin (BSA) rejection rate of 91.0 %. When the concentration of Ca2+ was increased to 10 mM, the Ca2+ catch amount increased to 48.25 mg/cm2. The main anti-fouling mechanism was that APIm captured a certain amount of Ca2+ in situ, destroyed the complex structure of sodium alginate (SA) and Ca2+. Then the fouling layer was easy to be removed by physical cleaning. At the concentration of 10 mM Ca2+, the membrane flux recovery rate of 1 v/v% APIm membrane was increased to 80.1 %. This study demonstrates a fouling control strategy for in-situ removal of Ca2+ bound SA fouling, providing a new approach for the future development of UF membrane.

Surface Damage by Physical Cleans during Semiconductors Manufacturing

This paper investigates surface damage caused by physical cleaning processes during semiconductor manufacturing. The study focuses on various materials, including FDSOI wafers and polymer films, subjected to high-velocity sprays and cryogenic cleans. Thanks to the supplier process performances and quality control, FDSOI films do not present any specific concern linked with this failure mode. This latter can be observed on whatever films exposed to aggressive physical cleans and the wafers are cleverly used as a test vehicle to evidence surface defects with a revelation method using a wet etchant. It enables the detection of nano-cracks and other damages. Same defects are observed in bulk silicon wafers, and solutions exist to avoid these damages. Different spray types are compared, highlighting the impact of droplet energy distribution on surface integrity. Additionally, a direct characterization method using polymer films is developed to assess physical cleaning damage. The findings emphasize the importance of optimizing cleaning processes to balance defect removal efficiency and surface preservation. Emerging cleaning solutions like polymer coat and peel methods are also discussed for their potential to offer high cleaning performance with minimal surface damage.

Constructing a stable photocatalytic functional layer through cross-linking of chitosan and l-mannose for efficient removal of doxycycline hydrochloride in single-pass flow mode

The development of technologies for effectively eliminating antibiotic pollutants from aquatic environments is crucial for preserving environmental quality. In this study, the 0D/3D Ag/AgI/MOF-808 photocatalysts were immobilized on the surface of polyethersulfone membrane using the Schiff-base reaction between chitosan and l-mannose to form a photocatalytic membrane (PES-CSLM-1) with a unique “sandwich” structure, which consists of a cross-linked layer, a functional layer, and a supporting layer. Under 240 min of visible light irradiation, the removal rate of doxycycline hydrochloride (DOX) (10 mg/L) by PES-CSLM-1 membrane was more than 90 %, which was 26.2 % higher than that of PES-CS membrane. The flux recovery rate of the membrane after photocatalytic self-cleaning reached 92.2 %, notably surpassing that achieved through physical cleaning (73.75 %), indicating that the photocatalysis effectively converted irreversible pollutants into reversible pollutants. After four cycles, the DOX removal efficiency of PES-CSLM-1 remained near 80 %, and the membrane structure and crystal structure did not change significantly. ·OH and ·O2− play important roles in the degradation process of DOX, and three potential degradation pathways for DOX were proposed. Toxicity analysis revealed that the environmental risk was significantly reduced during the DOX degradation process.

Optimising the hygiene of a liquid feeding system to improve the quality of liquid feed for pigs

Poor feeding system hygiene may contribute to uncontrolled spontaneous fermentation in liquid pig feed and its associated undesirable effects. This study aimed to determine the effects of an intensive sanitisation programme in a grow-finisher liquid feeding system by monitoring microbiological and physico-chemical parameters of liquid feed and microbial colonisation of the feeding system surfaces. The sanitisation programme involved a combination of physical and chemical cleaning between batches of grow-finisher pigs, combined with nightly rinsing of the system with an organic acid blend. Improved hygiene of the internal surfaces of the mixing tank and feed pipeline, particularly until week 5 post-cleaning, was evidenced by reduced counts of lactic acid bacteria, total aerobes, Enterobacteriaceae, yeasts and moulds and decreased adenosine triphosphate concentrations. Enterobacteriaceae and moulds remained undetectable on pipeline surfaces for 10 weeks. Scanning electron microscopy of the feed pipelines confirmed these findings. Conversely, the impact on liquid feed microbiology was minimal and short-lived. However, acetic acid, ethanol and biogenic amine concentrations decreased in the feed post-cleaning and no gross energy losses were observed. Therefore, by controlling surface microbial communities on liquid feeding systems via implementation of the sanitisation programme developed in the current study, on-farm liquid feed quality should be improved.

Treatment of textile wastewater in a single‐step moving bed‐membrane bioreactor: Comparison with conventional membrane bioreactor in terms of performance and membrane fouling

AbstractMembrane bioreactor (MBR) is a promising technology for the treatment of municipal and industrial wastewater, including highly contaminated textile wastewater. However, membrane fouling remains a critical challenge due to reduced flux. This study investigates the efficacy of a moving bed MBR (MB‐MBR) technology for textile wastewater treatment, focusing on chemical oxygen demand (COD) removal, and its impact on mitigating membrane fouling. In a 50‐day study, a conventional MBR (R1) was compared with an MB‐MBR (R2) augmented with free‐floating biocarriers (accounting for 20% of the reactor volume). Both systems used flat sheet ceramic membrane modules. The results indicate that the MB‐MBR achieved superior performance, with COD and colour removal of 89% and 81%, respectively, compared with 87% and 73% in the conventional MBR. Importantly, the introduction of biocarriers eliminated the need for offline physical membrane cleaning in the MB‐MBR. The free‐floating biocarriers lowered transmembrane pressure, reduced capillary suction time and reduced fouling through their scouring action.

Impact of membrane characteristics and chemical ageing on algal protein fouling behaviour of ultrafiltration membranes

Membrane characteristics can exacerbate the prevailing challenges associated with membrane fouling in industry. However, the combined impact of deliberate membrane modifications and the unavoidable effects of chemical ageing on fouling behaviour is still not well understood. In this study, three polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes with different pore size and surface roughness were selected and subject to chemical ageing with 5000 ppm sodium hypochlorite (NaOCl) at pH 10.5, selected to simulate accelerated ageing conditions. The impact of NaOCl on membrane characteristics was assessed for exposure times from 1.2 x 105 to 25.2 x 105 ppm·h using scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, contact angle, and clean water resistance analysis. The fouling behaviour of each pristine and aged membrane was compared using 10 mg C·L−1 dissolved organic carbon algal protein feed containing 18 % biopolymeric compounds. The membrane with intermediate pore size presented lower overall filtration resistance compared to the membrane with smaller pores that developed rapid foulant cake layers. It also displayed less susceptibility to fouling via pore blocking mechanisms compared to membranes with larger pores where greater surface area available in pore walls leads to higher foulant adhesion.

Femtosecond laser-induced nanoparticle implantation into flexible substrate for sensitive and reusable microfluidics SERS detection

Surface-enhanced Raman spectroscopy (SERS) microfluidic system, which enables rapid detection of chemical and biological analytes, offers an effective platform to monitor various food contaminants and disease diagnoses. The efficacy of SERS microfluidic systems is greatly dependent on the sensitivity and reusability of SERS detection substrates to ensure repeated use for prolonged periods. This study proposed a novel process of femtosecond laser nanoparticle array (NPA) implantation to achieve homogeneous forward transfer of gold NPA on a flexible polymer film and accurately integrated it within microfluidic chips for SERS detection. The implanted Au-NPA strips show a remarkable electromagnetic field enhancement with the factor of 9 × 108 during SERS detection of malachite green (MG) solution, achieving a detection limit lower than 10 ppt, far better than most laser-prepared SERS substrates. Furthermore, Au-NPA strips show excellent reusability after several physical and chemical cleaning, because of the robust embedment of laser-implanted NPA in flexible substrates. To demonstrate the performance of Au-NPA, a SERS microfluidic system is built to monitor the online oxidation reaction between MG/NaClO reactants, which helps infer the reaction path. The proposed method of nanoparticle implantation is more effective than the direct laser structuring technique. It provides better performance for SERS detection, robustness of detection, and substrate flexibility and has a wider range of applications for microfluidic systems without any negative impact.

Су беттерін және кәсіпорындардың ағынды суларын биоремедиациялау мәселесі бойынша

The problem of environmental protection from pollution by oil, petroleum products and industrial wastewater, as well as their disposal, is becoming increasingly acute due to the limited possibilities, and sometimes environmental insecurity, of using mechanical, physical and chemical cleaning methods for these purposes. In this regard, the possibility of using microorganisms capable of growing and displaying active biochemical activity in an environment with a high content of oil, petroleum products and industrial waste capable of biodegradation of these substances for purification purposes is relevant. The article analyzes the existing modern technologies for cleaning water surfaces and wastewater of industrial enterprises from oil and petroleum products pollution. Indicates the urgent need for the introduction of modern cleaning technologies, as well as the improvement of existing technologies. The article proposes modern methods of biological purification of water surfaces, bioremediation is a set of measures for cleaning soils and waters using the metabolic potential of biological objects. The use of microorganisms, insects, plants, algae, fungi is considered one of the most environmentally friendly and cost-effective technologies for cleaning at this stage

Optimum quorum quenching bacteria concentration in the better-quality cell entrapping beads to control biofouling in membrane bioreactor

Quorum quenching (QQ) by cell entrapping beads (CEBs) is known to inhibit biofouling by its biological and physical cleaning effect. Although there are better QQ media reported, due to the ease of fabrication of QQ-CEBs, this study focused on improving the quality of CEBs by comparing two distinct bead-making methods – polyvinyl alcohol-alginate (PVA-alginate) and phase inversion – and on finding the optimum concentration of QQ bacteria in the CEBs. The evaluation of PVA-alginate bead showed better uniformity, and higher mechanical and chemical strength in comparison with the phase inversion bead. Through the operations of two control membrane bioreactors (MBRs) (no bead, vacant bead) and four QQ-MBRs with different Rhodococcus sp. BH4 concentrations (2.5–15 mg cell ml−1) in PVA-alginate CEBs, the maximum QQ effect was observed by 5 mg ml−1 BH4 concentration beads. This implies that an optimum cell concentration of QQ-CEBs is crucial to economically improve MBR performance using QQ.

Impact of Cleaning on Membrane Performance during Surface Water Treatment: A Hybrid Process with Biological Ion Exchange and Gravity-Driven Membranes.

In this study, the hybrid biological ion exchange (BIEX) resin and gravity-driven membrane (GDM) process was employed for the treatment of coloured and turbid river water. The primary objective was to investigate the impact of both physical and chemical cleaning methods on ceramic and polymeric membranes in terms of their stabilised flux, flux recovery after physical/chemical cleaning, and permeate quality. To address these objectives, two types of MF and UF membranes were utilised (M1 = polymeric MF, M2 = polymeric UF, M3 = ceramic UF, and M4 = lab-made ceramic MF). Throughout the extended operation, the resin functioned initially in the primary ion exchange (IEX) region (NOM displacement with pre-charged chloride) and progressed to a secondary IEX stage (NOM displacement with bicarbonate and sulphate), while membrane flux remained stable. Subsequently, physical cleaning involved air/water backwash with two different flows and pressures, and chemical cleaning utilised NaOH at concentrations of 20 and 40 mM, as well as NaOCl at concentrations of 250 and 500 mg Cl2/L. These processes were carried out to assess flux recovery and identify fouling reversibility. The results indicate an endpoint of 1728 bed volumes (BVs) for the primary IEX region, while the secondary IEX continued up to 6528 BV. At the end of the operation, DOC and UVA254 removal in the effluent of the BIEX columns were 68% and 81%, respectively, compared to influent water. This was followed by 30% and 57% DOC and UVA254 removal using M4 (ceramic MF). The stabilised flux remained approximately 3.8-5.2 LMH both before and after the cleaning process, suggesting that membrane materials do not play a pivotal role. The mean stabilised flux of polymeric membranes increased after cleaning, whereas that of the ceramics decreased. Enhanced air-water backwash flow and pressure resulted in an increased removal of hydraulic reversible fouling, which was identified as the dominant fouling type. Ceramic membranes exhibited a higher removal of reversible hydraulic fouling than polymeric membranes. Chemical cleaning had a low impact on flux recovery; therefore, we recommend solely employing physical cleaning.

Electrochemical silica removal from carbon nanotube surfaces: Energy consumption and removal mechanisms

Inorganic fouling, or scaling, is a major challenge for engineered systems exposed to aqueous environments, particularly in water treatment, desalination, or thermal systems where the high salinity and temperature conditions favor surface scaling. Silica, in particular, is hard to remove once a scaling layer forms on the surface. Current scaling mitigation strategies include the addition of antiscalants, physical cleaning by flushing or backwashing, and pretreatment of the feed water. These mitigation strategies increase operation costs due to increased chemical use and system downtime, as well increase the complexity of the process. In this work, we investigated the ability of carbon nanotube (CNT) coatings to disperse silica from the surface via electrochemical reactions, providing a chemical-free approach to scaling control. Silica scaling was induced and then dispersed from CNT coupons upon the application of a potential difference across the experimental set up, with the CNT coupon acting as a cathode or anode. Scale removal was measured using optical coherence tomography at different applied current densities. In this study, a cathodic current of 2.5 A/m2 was found to achieve the highest silica removal: > 75% after 30 min. Control experiments conducted using pH-buffered solutions and pH-insensitive gypsum as the scaling mineral suggest that silica dispersion from the CNT surface was due to a combination of gas evolution and interfacial pH change. These results provide a better understanding of the potential of using electrochemical coatings for the removal of inorganic fouling from surfaces.

X-ray computed microtomography: A non-invasive and time-efficient method for identifying and screening Roman copper-based coins

This study utilises X-ray Computed Micro-Tomography (μXCT) as a non-destructive and non-invasive method to recover the original surface features and reveal the characteristics of encrusted, illegible Roman copper-based coins before any physical cleaning process is performed. The coins were retrieved from the topsoil during an archaeological survey in the countryside of the ancient city of Aquileia, Italy, and were severely degraded, covered with accumulated matter and pronounced encrustations developed over centuries of aging buried in soil. Despite their condition, most of the coins were identified from a numismatic standpoint using tomographic data alone, with the aid of reference images. They were subsequently cleaned using traditional manual methods and the results compared with μXCT. X-ray Fluorescence (XRF) analysis of the coins after the physical cleaning confirmed their numismatic attribution and revealed information regarding the influence of different alloy compositions on the applicability of the μXCT method, as well as on the corrosion process of the coins.This study showcases how the application of μXCT on fragile corroded metal artifacts prior to any intrusive manual procedures can expedite the identification process, mitigating the risk of information loss caused by physical handling and cleaning. This approach proves particularly valuable when dealing with large numbers of coins that would typically require restoration for identification purposes. It also emphasises the numerous advantages of using μXCT for coin identification, provenance determination, dating, virtual restoration, digitisation, and long-term preservation.

Pilot scale application of a rotating hollow fibre membrane for direct membrane filtration of domestic wastewater

This study investigates the direct ultrafiltration process of municipal wastewater (MWW) at pilot scale. Short-term trials were conducted with two membrane modules to assess the fouling mechanisms using different physical cleaning methods: gas sparging (hydraulic cleaning) and rotation (mechanical cleaning). This work demonstrates that membrane rotation effectively erodes and re-disperses external fouling during the backwashing stages. Consequently, shear stress generated by the rotational movement enables the operation with permeate fluxes ranging between 24 and 30 L/hm2, above the threshold flux value (22–24 L/hm2), while maintaining fouling rates (rf) below 10 Pa/s. In contrast, rf values increases up to 12.4–17.8 Pa/s when gas sparging is employed. Furthermore, the feasibility of up-concentrating municipal wastewater up to 12 times while operating with a net permeate flux of 20 L/hm2 is demonstrated through a long-term trial. The increase in suspended solids concentration (TSS = 5750 mg/L and VSS = 4750 mg/L) favours the rapid formation of a reversible cake on the membrane surface during filtration, at moderate transmembrane pressures (26 cmHg). These operating conditions avoid cake layer compression and protect the inner surface of the membrane module from severe internal residual fouling with an energy consumption of 0.027 kWh/m3.

Inhibition of Salmonella Enteritidis adhesion and biofilm formation by β-glucosidase B from Microbacterium sp. BG28

SalmonellaEnteritidis is the most commonly reported pathogen for foodborne illness outbreaks in both underdeveloped and developed regions. S. Enteritidis biofilms, which form on various food contact surfaces, are resistant to conventional physical and chemical cleaning and disinfection procedures routinely used in food processing. The aim of this study was to identify novel, industrially applicable enzymes that are active against S. Enteritidis biofilms. We describe the properties and anti-biofilm activity of heterologously expressed β-glucosidase B derived from the environmental strain Microbacterium sp. BG28 (BglB-BG28) collected from gills of bream fish. The enzyme inhibited adhesion and the early stages of biofilm formation in clinical isolates of S. Enteritidis. At a concentration of 200 μg/mL, BglB-BG28 effectively reduced biofilm formation, by decreasing biofilm biomass by 50% and metabolic activity within biofilms by 80%. The enzyme reduced the formation of air-liquid biofilms on various surfaces, including plastic, glass and metal, as observed by fluorescence microscopy. BglB-BG28 inhibited biofilm formation in Escherichia coli, another important food pathogen that also forms cellulose-rich biofilms. Using o-NPG as substrate, the enzyme showed activity at temperatures up to 50 °C and in a pH range between 4 and 8, high tolerance to sodium chloride and glucose, and compatibility with nonionic detergents. Importantly, no toxicity was observed in the model system Caenorhabditis elegans even at an enzyme concentration of 1 mg/mL. These results suggest that the β-glucosidase BglB-BG28 is a promising candidate for the development of a new enzyme-based disinfection protocol that can be used in food processing facilities.

Active teaching-learning methodology in the teaching of human anatomy: Preparation of skeletons from cemeterial exhums

Introduction: The study and teaching of human anatomy are important processes to understand how the human body presents itself and relates to other species. Osteology techniques are important for the classification of anatomical variations, scientific research tools and didactic use, and are performed through the physical, chemical or biological cleaning of bones to preserve the skeleton. Objective: To prepare, conserve, describe and catalog human bones from the Human Anatomy Laboratory of the Regional University Center of Espírito Santo do Pinhal, UniPinhal. Method: 50 complete human skeletons were donated to UniPinhal's Human Anatomy Laboratory and underwent a process of general and specific cleaning, disinfection, bleaching, drying, description, cataloging in its own database, conservation and storage. Result: All 50 skeletons underwent all processes, with 30% in good condition, 55% in medium or poor condition and 15% presenting pathological findings, such as bone malformations, fractures and vicious bone consolidation. The mean age at death was 64 ± 16 years. Most were male (67%, n = 33) and declared white (57%, n = 28). The most common cause of death was septic shock (31%, n = 15) and an estimated 40% (n = 20) of deaths were of unnatural causes. A total of 5729 bones were cataloged in the database. Conclusion: The male skeletons and the color declared as white are the largest number in the ossuary, and a third were in good condition for use in practical classes, scientific research, anatomical and forensic studies by students of Health courses.

Effect of temperature on organic fouling and cleaning efficiency of nanofiltration membranes for loch water treatment

We investigated the effect of solution temperature on organic fouling and cleaning of polypiperazine nanofiltration (NF) membranes. Fouling experiments were conducted in the temperature range 5 °C ≤ T ≤ 15 °C, characteristic of surface waters in northern latitudes, such as Scottish lochs. Results of laboratory-scale fouling experiments using alginate, a polysaccharide constituent of extracellular polymeric substances, showed a moderate increase in flux loss at 15 °C (41 %) compared to 5 °C (36 %). Analysis of the fouling experiments using a series-resistance model showed that the greater extent of fouling with rising temperature stems from a monotonic increase in water permeance with T. Interfacial property characterisation provided further insight into the effect of temperature on fouling determinants such as membrane hydrophobicity, nanoscale roughness, surface charge, and surface forces. No T-dependence of surface roughness was found. Similarly, we found that water contact angle is invariant within the temperature range investigated, suggesting that the observed fouling behaviour is not due to modulation of hydrophobic interactions. Conversely, colloidal-probe force spectroscopy (CPFS) measurements showed that adhesion forces become stronger with rising temperature. Further analysis showed that repulsive forces – which oppose colloidal particle deposition – become weaker with rising temperature, consistent with fouling trends. Determination of the membrane zeta potential showed that surface charge is invariant over the range of temperatures investigated, suggesting that repulsive forces have a non-electrostatic (likely steric) origin. Additionally, we assessed the effect of temperature on physical and chemical cleaning efficiency, comparing cleaning at the same temperature as the fouling experiments (5 °C ≤ T ≤ 15 °C) with cleaning at 30 °C. We observed that physical cleaning, consisting of water circulation over the fouled membrane surface, is insufficient to remove the foulant layers. On the other hand, chemical cleaning is able to restore 95 % of the original membrane permeance at 10 °C, but only 74 % at 5 °C.

Review—Post-Chemical Mechanical Planarization Cleaning Technology

Chemical mechanical planarization (CMP), a commonly employed process for attaining local and global planarization in integrated circuits fabrication, leaves contaminants and defects on the surface polished. Due to the miniaturization of devices, new materials/ processes for the fabrication of IC circuits are considered, introducing new post-CMP issues. So, understanding of post-CMP cleaning process is critical to choose an appropriate method for the given material. Thus, in this review paper, the types of contaminants and defects generated during the post-CMP process and the issues related to it are discussed. The different physical and chemical cleaning methods employed in the post-CMP cleaning process to eradicate these defects are elucidated. Especially, the PVA brushing method, which is mainly preferred currently, is elaborated on in detail. The various chemistries, including the newly suggested ones in recent years for cleaning different substrates, are summarized. The post-CMP cleaning methods for various materials such as Cu, Al, W, Co, Ru, InGaAs, Ge, and SiO2 are mainly addressed here. This review also provides the direction of progress for the post-CMP cleaning process in terms of evolution of new techniques and chemistries for the next generation of materials.

Pilot study of biofouling occurrence in a brackish water reverse osmosis system using intermittent operation

Water scarcity is a severe issue for humans owing to global climate change. Water reuse via reverse osmosis (RO) has been widely used to stabilize water supplies; however, RO membrane fouling increases operational costs and necessitates intermittent operation. The biofouling study on the RO pilot was operated either intermittently or continuously using collected brackish water. The environmental microbiome was incubated under oxic and anoxic conditions to simulate surface and groundwater conditions as the feed water. The least fouling was observed on the RO membrane surface when the RO system was operated intermittently using feed water incubated under anoxic conditions. The microbial results showed that specific biofilm communities were formed on RO membrane surface after brackish water RO (BWRO) operation. The major biofilm-forming bacteria distinctively differed with influent water conditions (i.e., oxic vs. anoxic), whereas they were less different with operational strategies (i.e., continuous vs. intermittent). Intermittent operation could compensate for physical cleaning. However, chemical cleaning showed the most effective results for microbe removal on the membrane surface. Therefore, intermittent operation using anoxic feed water can mitigate fouling formation on RO membranes.

PAN/TiO2 Ultrafiltration Membrane for Enhanced BSA Removal and Antifouling Performance

Membrane separation has been widely utilized to eliminate pollutants from wastewater. Among them, a polyacrylonitrile (PAN) ultrafiltration (UF) membrane has presented outstanding stability, and distinguished chemical and thermal properties. However, UF membranes inevitably incur fouling issues during their operation procedure caused by contaminant adhesion on the membrane surface, which would restrict the operational efficiency and increase the maintenance cost. The conventional physical and chemical cleaning is not an effective technique to reduce the fouling due to the additional chemical addition and inevitable structure damage. Recently, UF membranes combined with photocatalytic materials are suggested to be a useful approach to conquer the membrane fouling issues. Herein, TiO2 nanoparticles were utilized to blend with a PAN casting solution for fabricating a composite UF membrane via a phase inversion method. With a certain TiO2 addition, the obtained membranes presented an enhancement of hydrophilicity, which could promote the water permeability and antifouling performance. The optimized M3 membrane prepared with 15.0 wt% PAN and 0.6 wt% TiO2 exhibited an excellent water permeability up to 207.0 L m−2 h−1 bar−1 with an outstanding 99.0% BSA rejection and superior antifouling property. In addition, the photocatalytic TiO2 nanoparticles endowed the M3 membrane with a remarkable self-cleaning ability under the UV irradiation. This facile construction method offered new insight to enhance the UF membrane separation performance with an enhanced antifouling ability.

A physical coal cleaning approach for clean energy production from low grade Lakhra coal of Pakistan using diester table

In this work coal from Lakhra (coal mine in Pakistan) was subjected to a physical technique for mineral matter and sulfur reduction by using diester table. Effect of particle size and coal-to-water ratio of slurry were studied. A reduction of 85% in sulfur content and 88% in ash content for 500 µm coal sample was observed. While at 300 µm size sulfur and ash content were reduced about 77% and 80% respectively. At 150 µm size, the reduction in sulfur and ash was observed to be lesser (54% and 55% respectively) due to the decrease in specific gravity difference of coaland impurity (i.e. sulfur and ash). GCV increased from 17.2 MJ/kg of the raw coal to 23.3 MJ/kg of cleaner fraction obtained at 500 µm. Based on the results of this study, diester table can be proposed to be a simpler however an effective physical coal cleaning method to reduce sulfur and ash content. Besides other parameters, particle size is a crucial parameter to impact the cleaning efficiency and because of the greater difference in specific gravity of coal and impurity, higher particles size used in this study resulted in the cleanest product.