Chemical Treatment Processes Research Articles

Treatment of oil production wastewater by membrane bioreactor

<p>Wastewater generated in oil production and refinery industries contains high levels of pollutions. Water from the oil production field is the largest source of wastewater in the oil production and refinery industry. It can cause environmental problems on a global scale due to its high volume and pollutant properties. The treatment of produced water and refinery wastewater is traditionally carried out by physical, chemical, and biological treatment processes. In recent years, it has been focused on the use of membrane technologies. In the treatment of oil production wastewater, membrane bioreactors are used as pre-treatment and / or direct treatment methods. In this study, the treatability of wastewater generated in the oil production field by membrane bioreactor was investigated. The system has been operated for 70 days and its efficiency has been evaluated. Treatment parameters such as chemical oxygen demand, total solids, total nitrogen, total phosphorus, Alkalinity, and conductivity were analyzed. In addition, flux and transmembrane pressures were measured. Result, chemical oxygen demand, total solids, total volatile solids, suspended solids, total phosphorus, total nitrogen and sulfate, average removal efficiencies 65%, 65%, 58%, 73%, 70%, 50%, and 57% was obtained, respectively. It has been determined that the system used can be used in petroleum production wastewater treatment.</p>

Pemanfaatan Ozon Sebagai Teknologi Berkelanjutan Daur Ulang Air Limbah Domestik Hotel X Lembang

Domestic waste water comes from various daily human activities such as water from bathing or from toilets (feces and urine), used washing clothes, used washing cooking and eating utensils, leftover food or drinks in liquid form. WHO underlines the importance; management of human waste (feces and urine) safely, and disposed of safely. To reduce the negative impact on the environment, comprehensive and sustainable efforts are needed so that domestic wastewater can be disposed of safely or recycled so that it can be reused. This experiment was conducted in Lembang, West Bandung Regency, which took domestic wastewater from hotel X activities. The use of ozone in the wastewater recycling process is simpler than conventional chemical treatment processes that rely on chemical-based coagulants and flocculants, and has been shown to be able to reduce TSS. by 77.27%; Ammonia 96.17%; Oils & fats decreased 6%; Total Coliform 99.61% .. The use of ozone can be an option in the process of recycling domestic wastewater in a sustainable manner. environmental management is also related to the use of technology and methods in accordance with regional conditions and resource potential.

Influences of chemical treatment on sludge derived biochar; Physicochemical properties and potential sorption mechanisms of lead (II) and methylene blue

Unlike agricultural biomass, sludge-derived biochar is rich in nutrients, comprising exchangeable cations and various surface oxygen functional groups with carbonaceous structures. In this study, the influence of different activating reagents such as H3PO4, H2O2, K2CO3, and NaOH on the physicochemical properties of biochar was investigated. It was found that the biochar elemental composition remains nearly the same, while the surface Fe and Si were induced for H3PO4 modification. The pH of the original biochar was varied from acidic to alkali (3.60–10.06) along the chemical treatment process. The surface-active sites of biochar and their nature were dramatically tuned based on their chemical modification. To interpret the relationship between each of the parameters obtained via chemical modification, adsorption of different pollutants, such as Pb(II), Cd(II), Cr(VI), V(V), As(III), and methylene blue (MB) were conducted. Among the biochars, NaOH-modified biochar was revealed as the optimum candidate with maximum uptake capacity for Pb(II) (195.75 mg/g) and MB (160.78 mg/g). Based on the adsorption kinetics and isotherm study, the adsorption process endorsed chemical sorption with multiple interactions along the heterogeneous surface. This study offered a comprehensive approach to manipulating the physicochemical properties of biochar.

Pool boiling heat transfer and bubble dynamics of modified copper micro-structured surfaces

In this work, hydrophobic copper micro-structured (HCM) surfaces are prepared to improve boiling heat transfer. A combination of chemical etching and heat treatment processes is employed to make the bare copper surface hydrophobic in nature. With the modification of wettability, a different micro-structured feature is developed on the surface. The static contact angle of the prepared hydrophobic surface is varied in between 114° to 140°. A saturated pool boiling experiment is conducted at atmospheric pressure by taking distilled water as the boiling fluid. The maximum heat transfer coefficient is 119.7 kW/m2K for the HCM surface with a contact angle of 140°. Due to its hydrophobic nature, the critical heat flux (CHF) of the HCM surfaces is a little smaller than the bare copper surface. Bubble dynamics are also observed during boiling. The surface roughness of the HCM surfaces is enhanced, which increases the active nucleation site of the HCM surfaces. The bubble departure diameter of the HCM surfaces is smaller than the bare copper surface, with a maximum reduction of 45% for the HCM-3 surface. It is also found that the micro-porous surface prepared by a combination of two conventional processes increases the heat transfer substantially.

Coagulation Behavior of Antimony Oxyanions in Water: Influence of pH, Inorganic and Organic Matter on the Physicochemical Characteristics of Iron Precipitates.

The presence of inorganic and organic substances may alter the physicochemical properties of iron (Fe) salt precipitates, thereby stabilizing the antimony (Sb) oxyanions in potable water during the chemical treatment process. Therefore, the present study aimed to examine the surface characteristics, size of Fe flocs and coagulation performance of Sb oxyanions under different aqueous matrices. The results showed that surface properties of Fe flocs significantly varies with pH in both Sb(III, V) suspensions, thereby increasing the mobility of Sb(V) ions in alkaline conditions. The negligible change in surface characteristics of Fe flocs was observed in pure water and Sb(III, V) suspension at pH 7. The key role of Van der Waals forces of attraction as well as hydration force in the aggregation of early formed flocs were found, with greater agglomeration capability at higher more ferric chloride dosage. The higher Sb(V) loading decreased the size of Fe flocs and reversed the surface charge of precipitates, resulting in a significant reduction in Sb(V) removal efficiency. The competitive inhibition effect on Sb(III, V) removal was noticed in the presence of phosphate anions, owing to lowering of ζ-potential values towards more negative trajectory. The presence of hydrophobic organic matter (humic acid) significantly altered the surface characteristics of Fe flocs, thereby affecting the coagulation behavior of Sb in water as compared to the hydrophilic (salicylic acid). Overall, the findings of this research may provide a new insight into the variation in physicochemical characteristics of Fe flocs and Sb removal behavior in the presence of inorganic and organic compounds during the drinking water treatment process.

Superhydrophobic straw felt for oil absorption

Water pollution caused by oil spills, industrial and household wastewater seriously endangers environments and ecosystems. Commercially available oil absorption felts have been widely used in oil removal; however, their relatively poor absorption capacity and high cost restrict practical applications. Therefore, it is of great significance to develop a new oil-removing material with excellent oil absorption capacity and low cost. Here, a new kind of oil absorption felt originated from waste straw fibers is proposed. Waste rice straw fibers are formed into felts with special shapes by molds and further transferred into superhydrophobicity and superoleophilicity by a simple chemical treatment process. The superhydrophobic straw felts possess excellent absorption capacity for different oils with >95% oil/water separation efficiency. Weight of absorbed oil of the superhydrophobic straw felts is up to 2.55 times as much as that of commercially available oil absorption felts. More interestingly, the superhydrophobic straw felts are applicable to harsh conditions including strong turbulence, strongly acidic water, and intensive ultraviolet irradiation. Using waste rice straw fibers as raw materials, the superhydrophobic straw felts may have promising application prospect in the treatment of oil spills, industrial and household waste water.

Towards a Circular Economy: A Review on Asbestos Waste Management Regulations in Kenya

Kenya banned the use of asbestos in 2006, given its carcinogenic effects. Consequently, regulatory and institutional guidelines have been established to ensure the safe disposal of hazardous material. Yet, Kenya still uses 10% of its national health allocations to treat asbestos-related infirmities. The goal of this article is to review the policy guidelines for disposal of asbestos and assess its robustness as a measure of socio-environmental risk reduction. The study utilises a systematic review of policy guidelines on asbestos, air, and water quality regulations against their implementation reviewed in Environmental Impact Assessment reports from 2013 to 2021. Studies assessing thermal and chemical treatment processes for asbestos are reviewed to assess the processes involved and acquire information based on efficiency in terms of cost, technological applicability, and minimal environmental effects. The review shows that more risks are inherent from landfilling, which is considered safe in the regulations. Examples include compromised standards of disposal and unforeseen risks arising from geologic activity that may create channels for leaching and other exposure pathways. This review proposes that the policy guidelines should ‘rethink’ and adopt conversion of the substance through processes such as dissolution in acids (and) or thermal conversion processes. The processes guarantee the elimination of the fibres and yield by-products that can be further processed, namely, glass and fertilisers. Additionally, they reduce waste and relieve landfills while optimising land use. Despite the high initial costs, the merits of the process offer significant trade-offs. There is a need for comprehensive data collection, especially on volume, detailed geophysical information, type of Asbestos Containing Material and coherence of policy guidelines. This sets precedence for the adoption of a circular economy which Kenya is determined to embrace. Also, it will present an opportunity for research and innovation that will contribute to a global knowledge base.

Mechanical Enhancement of Composite Bricks Using Kenaf and Oil Palm Cellulose Nanofibrils

The application of nanocellulose has been adapted as fillers in composite bricks. Raw kenaf and oil palm empty fruit bunch were treated through chemical treatment and high intensity ultrasonication process to produce cellulose nanofibrils (CNF). One control brick without CNF and ten CNF composite bricks were fabricated. The composite bricks used different amount of CNF which were 40 - 200 ml mixed with filtered sand, portland cement and pebbles. Physical and mechanical characterization was done by using field emission scanning electron microscopy (FESEM) and universal testing machine (UTM) on CNF and composite bricks. FESEM showed the fibril diameter were ranges from 30 - 80 nm for kenaf and 20 - 60 nm for oil palm. The compression tests showed that control brick, 40 ml kenaf CNF composite brick and 40 ml oil palm CNF composite brick were cracked at force 39.01 kN, 50.46 kN and 42.16 kN respectively. Kenaf CNF composite brick has the highest value of Young’s Modulus which is 28.92 N/mm2, followed by oil palm CNF composite brick with 27.8 N/mm2 and control brick (Malaysia Standard) with 25.8 N/mm2. Kenaf and oil palm CNF can increase the strength of the bricks because of enhancement in their mechanical properties.

Treatment technologies for bakers' yeast production wastewater.

Researchers in recent years have utilized a broad spectrum of treatment technologies in treating bakers' yeast production wastewater. This paper aims to review the treatment technologies for the wastewater, compare the process technologies, discuss recent innovations, and propose future perspectives in the research area. The review observed that nanofiltration was the most effective membrane process for the treatment of the effluent (at >95% pollutant rejection). Other separation processes like adsorption and distillation had technical challenges of desorption, a poor fit for high pollutant load and cost limitations. Chemical treatment processes have varying levels of success but they are expensive and produce toxic sludge. Sludge production would be a hurdle when product recovery and reuse are targeted. It is difficult to make an outright choice of the best process for treating the effluent because each has its merits and demerits and an appropriate choice can be made when all factors are duly considered. The process intensification of the industrial-scale production of the bakers' yeast process will be a very direct approach, where the process optimisation, zero effluent discharge, and enhanced recovery of value-added product from the waste streams are important approaches that need to be taken into account.

Effective Chemical Coagulation Treatment Process for Cationic and Anionic Dyes Degradation

Effective Chemical Coagulation Treatment Process for Cationic and Anionic Dyes Degradation

Effects of natural-based SiO2 nanocoolant on car radiator: Thermal profile

Nanofluid as a transport medium has a great deal of potential in heat transfer engineering applications. In this work, nanosilica was derived from natural sources, rice husk through incineration and chemical treatment process. Various SiO2 nanoparticle volume concentrations (0–1 vol%) were dispersed in EG/water binary mixture assisted by ultrasound technique to produce SiO2 nanocoolant. Scanning Electron Microscopy (SEM) was used to identify the surface morphology and size of the nanosilica. Furhermore, the study was further conducted in a car radiator to determine the thermal profile consists of the effect of nanoparticle concentration and the longevity testing of the nanocoolant. Findings show that nanosilica particles were in range of 15–25 nm with irregular shape. Moreover, the heat transfer performance was enhanced as the SiO2 concentration was increased. Apart from that, SiO2 1 vol% shows a great thermal behaviour as it takes a shorter time to achieve and maintain at optimal working temperature compared to other samples. Apart from that, it can be observed that SiO2 nanocoolant possesses slightly higher properties than the base fluid and conventional coolant. The results also revealed the average heat transfer coefficient is directly proportional to the volume concentration of nanofluids and the heat transfer performance of the radiator increased with the inclusion of nanoparticles to the base fluid.

Organic material removal from bilge water by chemical treatment processes

Organic material removal from bilge water by chemical treatment processes

Fabrics for the circular economy

It is difficult to remove the chemicals and finishing substances commonly used to enhance sun protection in awnings and outdoor furnishings, which represents a major hurdle in terms of recycling acrylic waste from these products. Researchers in the REACT project are developing a chemical treatment process to enable the re-use of acrylic textile waste, as Daniele Piga explains.

The influence of particle size on the extraction of cellulose nanofibers using chemical-ultrasonic process

Chemo-mechanical method is the effective method for extracting cellulose nanofibers from agricultural biomass. Objective of this research was to study the impacts of rice straw with different particle size distributions, on the yield and ultimate properties of cellulose nanofibers (CNF). Rice straw with two different particle size distributions (less than 75 μm and between 150 and 250 μm) were investigated. It was observed that after the stepwise chemical treatment processes, rice straw sample less than 75 μm particle size yielded 27.19 ± 0.99 % and rice straw sample between particle size 150 to 250 μm yielded 38.31 ± 0.85 %. From the extracted cellulose fibers, 64 % CNF was extracted from particle size less than 75 μm sample and 55 % of CNF from particle size between 150 and 250 μm sample via ultrasonic process. Structural, thermal and morphological properties of CNF and its intermediates were ascertained. The study revealed that the particle size of raw material rice straw had a significant effect on properties and yield of extracted cellulose nanofibers.

A review on ultrasound and photocatalysis-based combined treatment processes for pesticide degradation

Pesticides such as fungicides, insecticides, and herbicides, which are frequently used in agricultural applications and have adverse effects on humans and pollute the environment, are the leading cause of production. There are several strategies for removing pesticides, including traditional techniques that include physical, chemical, and biological treatment processes, although they are not very effective in removing pesticides. Because of the intense creation of oxidative free radicals, advanced oxidation processes (AOPs) have recently received a lot of interest. For the mineralization of many organic compounds, AOPs are more successful when photocatalysis and ultrasound are combined. We explore how degradation is affected by many parameters such as catalyst loading, light intensity, pH of the solution, initial pesticide concentrations, support-based catalysts, and suspended catalysts in this review paper. This review also summarizes existing studies on pesticide degradation using a combination of ultrasonic and photocatalysis technologies, which is critical for reducing environmental problems related to pesticides.

Design and processing optimization of hollow grouted bolt for failure prevention

Hollow grouted bolt is an important component of slope reinforcement for structures like skyscrapers, tunnels, railways, highways, bridge foundations and dykes etc. The mechanical properties of it are significant for ensuring the safety and reliability of the structures reinforced, particularly the yield ratio, which must not exceed 0.8 according to the technical standard. For the purpose of alloy elements saving and production costs reduction, as well as for failure prevention, this paper endeavors to substitute the 45 carbon steel (equivalent to the ISO C45E4) for the Q345B low alloy steel (equivalent to the ISO E355DD) to produce the hollow grouted bolt, and focuses on the influencing factors in the processing technology to achieve the desirable properties. In detail, different designs in the chemical compositions, deformation extents and heat treatment processes were proposed and testified to figure out the optimum means for producing the 45 carbon steel hollow grouted bolts. Especially, a novel heat treatment process that applied the high-frequency rapid heating technology in hot rolling was also proposed for energy saving and efficiency improvement. On the finished bolts, the direct reading optical emission spectrometer, metallographic microscope and universal testing machine were utilized to evaluate the compositions, structures and properties. In addition, finite element analysis was performed on the hollow grouted bolts to evaluate the reliability in the application scenario of tunnel excavation. Achievement of this paper would have some reference values for failure prevention of the hollow grouted bolts serving under the similar engineering environments.

New approach of recycling end-of-life reverse osmosis membranes via sonication for microfiltration process

Due to the continuing growth of reverse osmosis (RO) water treatment plants worldwide, the amount of discarded end-of-life (EoL) RO membrane modules is expected to increase drastically in coming years. One of the approaches to address this problem is to transform the EoL membranes for other purposes. In this study, a new approach based on sonication was studied to convert the EoL RO membrane from RO properties into microfiltration (MF) properties, offering a transformation process that was much faster (15 min) than that of typical chemical treatment process (ranging from hours to days) using oxidizing agent solution. Our results indicated that with only 15-min ultrasonication, the properties of EoL RO membrane could be significantly altered, reaching pure water permeability of 172.6 L/m2.h.bar (70-fold increment) with NaCl rejection reduced from ~80% to less than 2%. This is attributed to the deterioration of the polyamide thin selective layer atop the EoL RO membrane. As a comparison, the chemical treatment using 5000-ppm potassium permanganate (KMnO4) solution requires at least 168 h to achieve similar membrane properties. It was also found that the presence of KMnO4 during ultrasonication process could accelerate the rate of polymeric degradation, resulting in even higher pure water permeation. As a conclusion, our work demonstrated a rapid and new approach that is capable of transforming the EoL RO membrane for the filtration process of macromolecules, thus offering a practical solution to address the disposal issues of EoL RO membrane modules.

Effects of silane treatment on the bond between steel fibres and mortar

The ability of fibres to resist crack growth in fibre-reinforced concrete can be significantly influenced by the fibre–matrix bond. This investigation reveals surface treatment of fibres as a viable technique for developing a uniform bond along the fibre–cement interface to resist growth of microcracks and thereby complement the physical restraint against pull-out provided by fibres’ shape and friction. Previous reports have shown effective chemical treatment of glass, carbon and polypropylene fibres. However, research into chemical surface treatment processes for steel fibres, the most common in concrete, is scarce and focused on corrosion and dispersion, rather than the fibre–matrix bond. Here, a silane treatment technique is proposed to strengthen the steel fibre–cementitious matrix bond. Surface energy measurements and X-ray photoelectron spectroscopy demonstrate the effectiveness of this treatment. Fibre pull-out tests conducted on silane-treated fibres show an apparent increase in pull-out energy, accompanied by a delay in reaching the peak load, compared with untreated fibres, suggesting increased resistance to crack initiation and growth. Furthermore, the results indicate improved flexural strength and direct tensile strength of mortar reinforced with silane-treated fibres compared with untreated fibres. The improvements are further corroborated by results from restrained drying shrinkage and volume of permeable voids.

Hardened wood as a renewable alternative to steel and plastic

Hardened wood as a renewable alternative to steel and plastic

Thermally conducting yet electrically insulating epoxy nanocomposites containing aluminum@electrochemically exfoliated graphene hybrid

The development of miniaturized and highly integrated microelectronic products has motivated the current importance of synthesizing heat-dissipation materials with high thermal conductivity and excellent electrical insulation. Although graphene is attractive for improving the thermal conductivity of polymers owing to its high aspect ratio and outstanding thermal conductivity, it significantly deteriorates electrical insulation capability, limiting its practical application in polymer composites for thermal management of electronics and systems. In this work, we used planetary ball milling to synthesize a hybrid powder Al@EEG consisting of electrochemically exfoliated graphene (EEG) and surface-passivated aluminum particles. This ball milling prevents contact between graphene sheets by uniformly dispersing EEG in Al matrices without the conventional surface modification or chemical treatment process of graphene, thereby imparting thermal conductivity and electrical insulation to the hybrid powder. The resulting epoxy composite, containing 35- wt% Al@EEG hybrid, retains an electrical resistance of 1014 Ω·cm or higher and a thermal conductivity of 1.43 W m−1 K−1, which is 499% higher than that of neat epoxy. The as-designed material points the way to polymer-based, thermally conductive, electrically insulating composites for various electronic components such as printed circuit boards and light-emitting diode driver cases.