Search

This article presents a compact, low-cost, robust, and flexible test platform for determining the concentration of drugs in fluids. This device is based on a PVC foil card containing copper conductive foils in which disposable paper test strips are inserted. The paper test strips are overlaid with deposition of multiwalled carbon nanotubes (MWCNTs) acting as a sensing layer. When a paper test strip is inserted into the test card, the conductive path between two copper lines is established. A drop of test fluid on the sensing MWCNT layer changes the conductivity in a concentration-dependent manner, enabling calculation of the drug concentration after measurement of the electrical resistance at the copper terminals. An equivalent electrical circuit was also proposed to model the response of the fabricated sensor. It was shown that model parameters are dependent on the concentration of the cytostatic drug methotrexate. Additionally, the fabricated sensor demonstrated the ability to differentiate the same concentration of methotrexate and cyclophosphamide. The complete readout electronics and polynomial transfer function for calculating drug concentrations were also developed and are presented.

Characterization and optimization of paper SERS substrate were performed in detail, in which morphologies and distribution of silver nanoparticles (AgNPs) on the paper substrate pretreated with different concentrations of NaCl and the subsequent soaking with colloidal AgNPs for different period of time were evaluated. Our results show that both NaCl concentration and soaking time with AgNPs have a significant influence on SERS enhancement, showing that an optimal EF of 2.27 × 107 was achieved when the paper substrate was treated with 20 mM NaCl and one-hour soak with AgNPs. Moreover, seminal plasma (SP) was specifically selected to evaluate the performance of paper-based SERS substrate for potential clinical detection and diagnosis. The optimization of the paper SERS substrate demonstrates potential applications in reliable on-site detection of SP and clinical diagnosis of fertility-related diseases as well.

Data envelopment analysis (DEA) as a nonparametric programming approach has been widely extended and applied in many areas. Conventional DEA models can well measure the efficiency of inefficient decision-making units (DMUs) but cannot further discriminate the efficient DMUs. A lot of methods are proposed to address this problem. One of the most important methods is the slacks-based measure of super-efficiency model (S-SBM model) developed by Tone in 2002. However, the projection for a DMU on the efficient frontier identified by S-SBM model may not be strongly Pareto-efficient that makes the super-efficiency score misestimated. This paper revises the usual slacks-based measure of super-efficiency by incorporating input saving and output surplus scaling factors into the objection function for measuring DMUs. We integrate SBM model and S-SBM model effectively and yield input saving and output surplus scaling factors as well as input and output slacks under only one integrated model. According to the study, the projection reference point identified by our method is strongly Pareto-efficient. Meanwhile, how each decision variable influences the efficiency score for a specific DMU is revealed and illustrated through two numerical examples and an empirical study in paper chemical mills.

Face-centered composite design (FCC) was used to study the effect of pulping variables: soda concentration (4-5 wt%), temperature (90–130°C), and pulping time (20–60 min) on the properties of pineapple leaf pulp and paper employing soda pulping. Studied pulp responses were screened yield and lignin content (kappa number). Paper properties, which include tensile index, burst index, and tear index, were also investigated. Effects of the pulping variables on the properties were statistically analyzed using Minitab 16. The optimum conditions to obtain the maximum tensile index were soda concentration of 4 wt%, pulping temperature of 105°C, and pulping time of 20 min. The predicted optimum conditions provided tensile index, burst index, tear index, screened yield, and kappa number of 44.13 kN·m/kg, 1.76 kPa·m2, 1.68 N·m2/kg, 21.29 wt%, and 28.12, respectively, and were experimentally confirmed.

Nanofibrillated cellulose (NFC) isolated from TEMPO-oxidized rice straw was used to improve thermal and tensile strength properties of acrylate polymer films. Acrylate/NFC mixture containing 15% NFC was used for paper coating, and properties of paper sheets including tensile strength, water absorption, and microscopic structure were investigated. The results showed that the presence of NFC in the acrylate matrix significantly improved tensile strength properties and thermomechanical properties of the acrylate polymer and caused moderate increase in its moisture sorption. The presence of NFC in acrylate emulsion caused significant increase in its viscosity. Paper sheets coated with different thin layers (from 0.2 to 6 microns) of acrylate/NFC showed improvement in tensile strength and decrease of water absorption.

Electronic capacitors were constructed via hand-printing on paper using pencil graphite. Graphite traces were used to draw conductive connections and capacitor plates on opposing sides of a sheet of standard notebook paper. The paper served as the dielectric separating the plates. Capacitance of the devices was generally < 1000 pF and scaled with surface area of the plate electrodes. By combining a pencil-drawn capacitor with an additional resistive pencil trace, an RC low-pass filter was demonstrated. Further utility of the pencil-on-paper devices was demonstrated through description of a capacitive force transducer and reversible chemical sensing. The latter was achieved for water vapor when the hygroscopic cellulose matrix of the paper capacitor’s dielectric adsorbed water. The construction and demonstration of pencil-on-paper capacitive elements broadens the scope of paper-based electronic circuits while allowing new opportunities in the rapidly expanding field of paper-based sensors.

Multiwalled carbon nanotube/cellulose composite papers have been prepared by mixing the cellulose with MWNT/gelatin solution and drying at room temperature. The CNTs form an interconnected network on the cellulose paper and as a result CNT paper sheet exhibits enhanced electrical properties and thermal stabilities. It is found that both sides of CNT paper sheet have the uniform electrical conductivities. The sheet exhibits strong microwave absorption in the microwave range of 10.5 GHz. The CNT/cellulose paper is as flexible and mechanically tough as the pure cellulose paper. This work provides a novel and simple pathway to make CNT/cellulose sheet as multifunctional biomaterials for electronic, magnetic, semiconducting, and biotechnological applications.

Vacuum-assisted resin transfer molding (VARTM) process was used to fabricate the nanocomposites through integrating carbon nanofiber paper into traditional glass fiber reinforced composites. The carbon nanofiber paper had a porous structure with highly entangled carbon nanofibers and short glass fibers. In this study, the carbon nanofiber paper was employed as an interlayer and surface layer of composite laminates to enhance the damping properties. Experiments conducted using the nanocomposite beam indicated up to 200–700% increase of the damping ratios at higher frequencies. The scanning electron microscopy (SEM) characterization of the carbon nanofiber paper and the nanocomposites was also conducted to investigate the impregnation of carbon nanofiber paper by the resin during the VARTM process and the mechanics of damping augmentation. The study showed a complete penetration of the resin through the carbon nanofiber paper. The connectivities between carbon nanofibers and short glass fibers within the carbon nanofiber paper were responsible for the significant energy dissipation in the nanocomposites during the damping tests.

In mineral flotation, rheological problems have limited the efficient upgrading of low-grade and complex ores. Since pulp and froth rheology are deemed to play different roles in influencing the separation performance, in this paper, a brief review on pulp and froth rheology in flotation is provided, with an objective of developing a basic understanding of rheology in flotation. The essential variables that affect the rheology of a flotation pulp and froth are discussed. The methods for measuring pulp and froth rheology are presented. The correlations of pulp and froth rheological properties to flotation performance are reviewed. Strategies that are currently used to mitigate the deleterious effects of problematic ores in flotation are also provided for flotation optimization. Research gaps are also proposed to highlight the need of further exploration of flotation rheology in future.

Dyes and other chemicals laden wastewater is a main environmental concern for increasing the textile industries in many parts of the world. Textile industries consume different kinds of manmade dyes or other chemicals and release huge extents of highly polluted water into the environment. This excessive dye laden wastewater has great impacts on photosynthetic activity in aquatic plants and animals, for example, fish. It may also affect human health due to the presence of components like heavy metals and chlorine in manmade dyes. Thus, wastewater effluent from textile industries must be treated before discharge into the water body. Treatment technologies observed in this review paper include biological treatment methods (fungi, algae, bacteria, and microbial fuel cells), chemical treatment methods (photocatalytic oxidation, ozone, and Fenton’s process), and physicochemical treatment methods (adsorption, ion exchange, coagulation, and filtration). This review also includes the hybrid treatment methods and their cost per m3 of treated wastewater analysis. There are alternative wastewater treatments systems at different steps of effluent generated from the textile operational unit recommend in this review work.

This paper reports leach and/or intake of SO42−, Cl−, Ca2+, Na+, and K+ from and/or into cement mortar cubes made from a novel cementious material in naturally encountered environmental simulated media. The paper also reports changes in pH of the media over time of exposure to the cement mortar cubes. The compressive strength changes of the test cement in simulated media are also reported. The novel cement, labelled PCDC, made from intermixing ordinary Portland cement (OPC) with waste materials which included rice husks, waste bricks, acetylene lime sludge, and spent bleaching earth was previously tested and found to meet the Kenyan Standard requirements for Portland pozzolana cement (PPC). 100 mm mortar cubes were prepared, and their compressive strengths were determined after exposure to the sea water. The media included sea water, distilled water, and solutions of sulphates and chlorides separately for a period of six months. The tests were carried alongside commercial PPC and OPC. The results showed that the PCDC exhibited comparable selected ions intake and/or leach to PPC in sea water, sulphate solutions, and distilled water. In chloride solutions, the cement exhibited the highest leach in the selected ions except K+ and Na+ ions. The results further showed that PCDC exhibited lower pH in all the media compared to OPC and PPC. The tests showed that the novel cement can be used for general construction work in the tested media in a similar manner to PPC.

In recent years, the removal of dyes from wastewater has attracted considerable attention due to their harmful effects to ecosystem and human health. Adsorption as a facile and effective technique has been widely used to eliminate a large variety of dyes from aqueous solutions. Activated carbon is the most preferred adsorbent to treat wastewater but its use is limited because of high cost. Therefore, several low-cost and natural materials and wastes have been used as precursors for the preparation of alternative adsorbents. Among them, sawdust as an abundant and low-cost by-product has been explored as adsorbent for the removal of dyes from wastewater. This review focuses on the various sawdust used as a precursor for the preparation of activated carbons. Extensive literature information about sawdust, its compositions, activation methods, its efficiency for dyes removal, and environmental conditions effects has been reviewed. The applicability of various adsorption kinetic models and adsorption isotherm models for dye removal by sawdust-derived activated carbons has been also reported. Finally, this paper highlights the use of sawdust as base material for various composites and mixture which can be used as granular activated carbon.

Lubricating oils degrade into two main products: oxidation products and solid particles. Oxidation products, called varnish, of turbine oils for power generation have become a particularly serious problem in recent years. The first step in determining the potential to produce varnish is to determine the remaining life of the antioxidant in the oil, but even though turbine oil may have antioxidants of sufficient longevity, varnish problems still occur frequently. Accordingly, to prevent varnish, it is necessary to diagnose oil oxidation products. Thus, the authors have developed a diagnostic method using membrane patch color, but the relationship between membrane patch color and the remaining life of turbine oils has yet to be clarified. This paper investigates a new method for estimating the oxidative degradation of turbine oils that uses membrane patch color and the dry turbine oxidation stability test (dry TOST) based on oxidation products and the remaining life of the turbine oils. Sample oils were prepared and degraded by oxidation in the laboratory using a dry TOST apparatus, and the membrane patch color was measured using a colorimetric patch analyzer (CPA). The relationship between membrane patch color and the rotating pressure vessel oxidation test (RPVOT) residual rate was then investigated. The results show that the new estimation method using the CPA and dry TOST is able to monitor the decrease of the RPVOT residual rate from the early stages of oxidative deterioration.

The world’s population is increasing rapidly. This means that energy consumption and demand for energy are also increasing at the same rate. It is estimated that energy will need to be provided to 9 to 10 billion people by 2040. India is a leading consumer of energy in the world. In particular, it consumes a large amount of oil and natural gas to fulfil its energy demand. Due to uncertainty in the supply of oil and natural gas and their prices as well as environmental pollution, there is a need to shift towards other energy sources. Biomass is one of the first energy sources with specific properties and abundant availability. Today, 10% to 14% of the world’s energy supply is provided by biomass sources. Using agricultural waste (biomass) to make briquettes to generate power can be an alternative solution to the problems related to their disposal and pollution. The present work investigates the optimum ratio of dry sugarcane leaves to binders and optimum load and selects the best binder (cow dung, buffalo dung, and press mud) for making high-quality briquettes. The physical parameters and proximate analysis of the dry sugarcane leaf briquettes with the cow dung, buffalo dung, and press mud binders are investigated. The dry sugarcane leaf briquettes with the cow dung binder have the highest gross calorific value, net calorific value, split tensile strength, tumbling resistance, shatter resistance, and energy density ratio (16262.31 kJ/kg, 15362.1 kJ/kg, 7.164 kN/m2, 87.84%, 12.75%, and 0.9296, respectively). The estimated results show that cow dung is a better binder for making high-quality dry sugarcane leaf briquettes than the buffalo dung and press mud binders.

The replacement of substances that favor the manufacturing of utility blocks ingredients is unpredictable in modern research. The experimental approach structured for the present investigation considered partial substitution of the cement mantle of a concrete matrix with dried fly ash sediment powder. As exploring innovation in being treated, dye wastewater is used in place of precious potable water for preparing mix ratio. The experimental outcomes were strongly supported by a regression representation at a macrolevel analysis and a scanning electron microscopy analysis at a microstructural level. The correlation coefficient of the developed mathematical models exhibited a dependable correlation of more than 90%. This shows the reliability of the developed regression equation for base strength predictions. Accordingly, the eventual safer and optimal limit of proportioning such a foreign matter like the dried fly ash sediment powder usage is controlled, not exceeding 9% by weight of cement mantle. However, due to the infused sediment particles within the treated effluents, the potable water is 100% replaced without sacrificing the basic quality. The administration of this dye effluent in artificially constructed wetland methods is designed for sustainable water conservation.

Wheat straw was utilized in the preparation of polycarboxylate superplasticizer (PCS) to improve its performance as well as to reduce the production cost in this paper. The addition time and pretreatment time of wheat straw in the production of PCS were detected. Orthogonal experimental design was adopted to optimize the components of reactants, and the adding time of the initiator was also examined. The PCS produced with wheat straw in this paper kept a rather high water-reducing rate. In addition, the results of some physical characteristics showed there were no obvious differences between the PCS produced with and without wheat straw, while the PCS produced with wheat straw had the longer time of coagulation. At the same time, infrared spectrum implied that the addition of wheat straw made the side chain more abundant and had little influence on the main chain of the large molecules.

Most of the rural transportation system is composed of two-lane highways, and many of them serve as the primary means for rural access to urban areas and freeways. In some highways, traffic volumes can be not high enough to justify a four-lane highway but higher than can be served by isolated passing lanes, or can present high number of head-on collisions. In those conditions, 2 + 1 highways are potentially applicable. This type of highway is used to provide high-performance highways as intermediate solution between the common two-lane highway and the freeway. Successful experiences reported in Germany, Sweden, Finland, Poland, or Texas (US) may suggest that they are potentially applicable in other countries. The objective of this white paper is to provide an overview of the past practice in 2 + 1 highways and discuss the research directions and challenges in this field, specially focusing on, but not limited to, operational research in association with the activities of the Subcommittee on Two-Lane Highways (AHB40 2.2) of the Transportation Research Board. The significance of this paper is twofold: (1) it provides wider coverage of past 2 + 1 highways design and evaluation, and (2) it discusses future directions of this field. The authors wish to thank the Fundación Agustín de Betancourt from the Universidad Politécnica de Cartagena for funding the research.

In the process of large-scale urban construction, large amounts of waste slurry are produced. The slurry has a high water content and is difficult to precipitate naturally, resulting in low treatment efficiency. To improve the treatment efficiency of slurry, a variety of inorganic and organic polymer flocculants were used to carry out flocculation settlement tests on the slurry. The changes in the slurry properties and the filtration dewatering effect after flocculation were tested. The results show that the addition of flocculant makes the slurry particles form aggregates, which leads to rapid precipitation of the slurry. The use of an inorganic flocculant significantly reduced the zeta potential of the slurry. Organic polymer flocculant, however, had little effect on the slurry potential, but did cause the slurry to produce larger size aggregates, resulting in a better flocculation effect than inorganic flocculant. Inorganic flocculants and organic flocculants can improve the pressure filtration dewatering performance of slurry. CPAM12 (cationic polyacrylamide, with a relative molecular weight of 12 million Daltons) had the best overall effect. The formation of aggregates after flocculation and the change in the nonuniformity coefficient (Cu) were the main cause of improvement of pressure filtration dewatering performance of the slurry. When Cu decreases from 11.85 to 8.75, the time required for pressure filtration stabilization is shortened by 70%. The nonuniformity coefficient of flocculated slurry can be used to evaluate flocculants, determine the optimal dosage, and predict the dewatering effect.

The research study was conducted to design the ultrasonic-assisted electrochemical reactor and the bioreactor/filter to evaluate the potential applicability of biological trickling filter system and to compare the efficiency of two reactors such as SER and TF for the treatment of textile industry effluents. Also the study to design Sonoelectrolytic process for wastewater treatment of textile industry containing strong color, high temperature, suspended particles and dissolved solid particles has been conducted. Effect to environment and health is caused by oxygen demand (BOD), high chemical oxygen demand (COD). The percentage removal efficiency for wastewater treatment of textile industry by using sonoelectrolytic reactor (SER) was found to be higher than 95% at temperature of 25°C and a pH value of 8.9, while for trickling filter (TF), having adsorbent as a filter medium, efficiency was found to be 95%, and optimum conditions obtained were applied for the treatment of different dye samples. Based on experimental outcomes, it is determined that treatment through SER is done faster than trickling filter because in TF the adsorbent capacity decreases with time and is a time-consuming process, but the chance of deposition on electrodes also increases in SER, so both these processes can yield better results if these problems are eliminated.

Focusing on the tailings containing high sodium silicate (water glass), this study conducted laboratory experiments and semi-industrial tests of flocculation and sedimentation for rapid tailings dewatering. Various reagent combinations, lime and anionic flocculant (APAM) (L&A), sulfuric acid and APAM (S&A), and calcium chloride and APAM (C&A), were tested. The results show that (i) all the three combinations presented a good effect in the laboratory experiments, and the relatively optimum dosages were L&A of 2 kg/t & 30 g/t, S&A of 2.6 kg/t & 20 g/t, and C&A of 3 kg/t & 30 g/t. (ii) The overflow water of the L&A group became turbid after 10 hours, and the pH increased to 14. While, for the S&A and C&A groups, the solid content in overflow wastewater (SCOW) fluctuated over time but could be mostly controlled in 300 ppm. The pH declined from 7 to 4 with time in the S&A group, and it was 7-8 in the C&A group. (iv) Thus, a backfill system with dewatering technology based on the C&A combination was designed. In the field application, the overflow water was recycled with the SCOW of less than 250 ppm and the pH of 7.5, while the underflow concentration was greater than 70 wt.%. The achievement provides a way to utilize the tailings containing sodium silicate effectively and environmentally, which will reduce the tailings dam on the Earth.

The most common effluent created by the oil industry is oily wastewater. This produced water (PW) corrodes the steel piles in the infrastructure of bridges, which shortens their service life. It is important to remove organic content in PW to prevent this outcome. Samples from the Ahdab oil field were used in this study. Two catalysts were selected: zinc oxide (ZnO) and titanium dioxide (TiO2) with photo presence as an energy source. The results were organic elimination of 96.4% and 93.4% using ZnO and TiO2, respectively. The experimental conditions were pH = 3 and an irradiation time of 120 min. Due to the ability of ZnO to adsorb high amounts of organic content from PW, there was an increased elimination of organic content. Hence, the maintenance of steel piles durability is a good alternative to approach the goals of this study. The results of the study demonstrated that the organic adsorption on a catalyst agent reinforced in nonappearance of radiation photo is insignificant.

Cyanidation is widely used by most gold mine worldwide and will remain prevail in years (or decades) to come, while cyanide is hazardous, toxic pollutants whose presence in wastewater and tailings can seriously affect human and its environment; hence, it is necessary to control these contaminants. The purpose of this study was to examine the effects through the investigation of changes in pH, concentration, and contact time, and the optimal conditions were obtained. It has been proven that the decomposition of cyanide in solution and tailings increased as the alkalinity in the presence of 0.5 g/L Na2S2O5. An increase in H2O2 (30%) concentration (from 1 to 4 mL/L) increased the decomposition in solution, while the effect on removing cyanide was better when pH was 9 than 8 and 10 in tailings. The cyanide in tailings decreased in the first 4 h and increased after 4 h. The effective and economic conditions for maximum decomposition of cyanide from leach tailings are first treated in 0.5 g/L Na2S2O5 at pH 10 for 3 hours and then 2 mL/L H2O2 (30%) is added to the tailings at pH 9 for 4 hours through comparative study. The findings provide the basis to optimize the decomposition of cyanide from gold leaching tailings in mining or backfilling by using the synergetic effect of Na2S2O5 and H2O2.

Although little attention is paid to corrosion study in food processing and production industry, it is highly important to take a critical look at what transpires at the production stages and how these can affect human health due to contamination of the final product. This research employs the design of experiment module of a Minitab software to analyze the corrosion effect of mild steel in fruit juice environment. Coupon method was adopted to calculate the rate of corrosion in orange, pineapple, and cashew fluid for a duration of 25 days with measurement taken at 5-day intervals. The highest corrosion rate of 0.71 mmpy was observed in cashew fluid followed by pineapple fluid, and the least rate of 0.08 mmpy was observed in orange fluid. The generalized model equation was obtained to predict corrosion rate of mild steel in a similar environment. In general, design of experiment offers a better way to analyze corrosion experiment result, and this innovative idea is shown in this work.

Agrifood by-products are a key element within Europe’s sustainable strategies. Valorization and reuse of zero-waste technologies are becoming more popular, and they are commonly named as “second-generation food waste management.” The present study is directed to the valuable extracts of “green” organic compounds from the by-products of fruit and berry/vegetable crops, which can be revalorized in sustainable chemical technology and engineering, namely, in the production of “green” synthesis of nanoparticles and for the inhibition of corrosion and scaling of metals in corrosive media. Numerous types of agrifood by-products (rapeseed pomace, sugar beet pulp, fodder radish cake, grape pomace, and pomegranate peels) were investigated. The waste extracts for corrosion and scale inhibitors of mild steel in tap water were prepared by the conventional extraction method that uses 2-propanol and characterized by gas chromatography-mass spectroscopy (GC-MS). Inhibition of scaling and corrosion was investigated in thermal scaling conditions on the surface of the electrode manufactured from mild steel. The LPR technique was applied to measure the corrosion rate, and the scaling rate was determined gravimetrically. The extracts were found to inhibit the corrosion rate 2-3 times, while only radish cake extract inhibited both the corrosion and scaling rates. The waste extracts to produce nanoparticles were prepared by the ultrasound-assisted water extraction with subsequent oxidation by oxygen purge and characterized by liquid chromatography-mass spectroscopy (LC-MS). The aqueous grape pomace and pomegranate peel extracts were screened for total phenolic content (TPC) and total flavonoid content (TFC). The reduction capacity of the extracts was assessed using ferric reducing power (FRAP) and phosphomolybdenum (PM) assays. AgNPs were characterized by UV-Vis spectroscopy, dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX) analysis. The particle size of AgNPs ranged between 40 and 50 nm. The antimicrobial activity of AgNPs was tested against Escherichia coli using the agar diffusion method and optical density.

This study deals with the removal of residual pollutants from tanning wastewater by continuous adsorption mechanism, using local sand as a low-cost adsorbent. The possibility of pretreating a complex tannery effluent heavily loaded with a natural material such as sand is significant. The characterization of the adsorbent before and after continuous adsorption was performed by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Column studies were also carried out to evaluate the performance of the adsorbent and the efficiency of column adsorption. The adsorption kinetic rate seems to be strongly influenced by certain parameters such as the particle size of the material used, the withdrawal rate of the influent and the height of the adsorbent bed, and optimized parameters were found to be 63 μm, 15 ml·min−1, and 7 cm, respectively, and the color removal has achieved maximum values which vary between 95 and 100%. The results suggest that sand can be used as an economical adsorbent for the removal of color from the wastewater of the tanning industries.

Perfluorooctanoic acid (PFOA) and microcystins are some of the well-known chemical contaminants in drinking water in the USA. Despite the availability of filtration technologies like ion-exchange resins, activated-carbon, and high-pressure membrane filters, these contaminants still remain widespread in the environment. In the present study, two innovative aspects of electrocoagulation techniques were tested, (a) cheap and easy-to-operate field-unit instead of hi-tech electrocoagulation and (b) reverse-polarity instead of conventional polarity, and applied to remove PFOA and microcystins from drinking water sources. The method presented here outperformed commercial activated-carbon filtration by nearly 40%. When the efficiency of electrocoagulation was examined in terms of voltage discharge, pH, and reverse-polarity, the results averaged 80% decontamination for individual treatment, while their combined effects produced 100% detoxification in 10–40 minutes, exceeding recently published results. The method shows great economic promise for water and wastewater treatment and chemical recycling.

The shortage of water resources in Saudi Arabia is becoming an increasingly serious problem. Management of sewage water is an attractive option to reduce the contamination of water resources such as ground water. This work aims to use bauxite rock as a low-cost adsorbent/coagulant for sewage water treatment in a simple and rapid technique. Different doses (1, 2, 3, 4 and 5 g/l) of the grinded bauxite was used as an adsorbent/coagulant. The results revealed that, at rock doses of 1, 2, 3, 4, and 5 g/l, the COD concentration was decreased from 326 to 134, 98, 83, 70, and 65 mg/l, respectively, while the BOD concentration was lowered from 243 to 196, 104, 71, 60, 51, and 47 for the same rock doses. This was reflected on the turbidity of the treated effluent from each treatment step. Also, the FC counts were reduced to 2 log units. Furthermore, the dose of 3 g/l of the grinded bauxite rock was found to be the least economic dose for the treatment of sewage water. Bauxite mineral has been used explicitly in a high-performance, very affordable method for wastewater treatment.

Textile industries generate large quantities of dye containing wastewater which pose a serious environmental problem. Currently, biosorbents have become desirable for the removal of dyes from textile effluents. In this study, batch experiments were conducted to investigate the biosorption characteristics of cactus peel on the removal of reactive red dye from aqueous solutions. The effects of solution pH, biosorbent dosage, contact time, and initial concentration were studied. The interaction effects of process variables were analysed using response surface methodology. The results showed that removal efficiency increased as initial dye concentration and solution pH decreased and as biosorbent dosage and contact time increased. The highest removal efficiency (99.43%) was achieved at solution pH, initial dye concentration, biosorbent dose, and contact time of 3.0, 40 mg/l, 6 g, and 120 min, respectively. From regression analysis, the Langmuir isotherm was found to better (R2 = 0.9935) represent the biosorption process as compared with the Freundlich isotherm (R2 = 0.9722). Similarly, the pseudo-second-order model was seen to represent very well the biosorption kinetics. The results show that cactus peel has good potential for the removal of reactive red dye.

Natural fibres are a gift from nature that we still underutilise. They can be classified into several groups, and bast natural fibre reinforcement in polymer composites has the most promising performance, among others. However, numerous factors have reported influences on mechanical properties of the fibre-reinforced composite, including natural fibre retting processes. In this review, bast fibre retting process and the effect of enzymatic retting on the fibre and fibre-reinforced polymer composites have been discussed and reviewed for the latest research studies. All retting methods except chemical and mechanical retting processes are involving secretion of enzymes by bacteria or fungi under controlled (enzymatic retting) or random conditions (water and dew retting). Besides, enzymatic retting is claimed to have more environmentally friendly wastewater products, shorter retting period, and controllable fibre biochemical components under mild incubation conditions. This review comprehensively assesses the enzymatic retting process for producing high-quality bast fibre and will become a reference for future development on bast fibre-reinforced polymer composites.

The release of wastewater from textile dyeing industrial sectors is a huge concern with regard to pollution as the treatment of these waters is truly a challenging process. Hence, this study investigates the triazo bond Direct Blue 71 (DB71) dye decolorization and degradation dye by a mixed bacterial culture in the deficiency source of carbon and nitrogen. The metagenomics analysis found that the microbial community consists of a major bacterial group of Acinetobacter (30%), Comamonas (11%), Aeromonadaceae (10%), Pseudomonas (10%), Flavobacterium (8%), Porphyromonadaceae (6%), and Enterobacteriaceae (4%). The richest phylum includes Proteobacteria (78.61%), followed by Bacteroidetes (14.48%) and Firmicutes (3.08%). The decolorization process optimization was effectively done by using response surface methodology (RSM) and artificial neural network (ANN). The experimental variables of dye concentration, yeast extract, and pH show a significant effect on DB71 dye decolorization percentage. Over a comparative scale, the ANN model has higher prediction and accuracy in the fitness compared to the RSM model proven by approximated R2 and AAD values. The results acquired signify an efficient decolorization of DB71 dye by a mixed bacterial culture.

The output of municipal solid waste (MSW) has sharply increased over the recent years, which induces many severe problems (environmental pollution, deteriorating human health, and increased land occupation). Engineering parameters form the research basis for MSW treatment, which can be greatly influenced by the applied sample preparation methods. Currently, the preparation method of MSW samples mostly refers to the geotechnical test standard. The suitability and accuracy of this method for MSW are less studied, especially when considering biodegradation, so further research is needed. Depending on whether the material is dried or remains wet during preparation, the samples made by traditional geotechnical test standards are referred to as dry method samples or wet method samples, respectively. To study the influence of the sample preparation methods on the MSW engineering properties of MSW, the compression tests, direct shear tests, and biodegradation compression tests were conducted for both types of samples (dry and wet). The results show that the data dispersion of the wet method samples is stronger. The average test data variance of wet samples was 1.43–8.85 times higher than that of dry samples. In both the direct shear test and the compression test, the differences in engineering parameters caused by the sample preparation method were less than 12.3% and 8.9%, respectively. In biodegradation compression tests, the difference in engineering parameters reached up to 33.7%. In general, the dry method is preferred for tests that do not consider biodegradation, while the wet method is more suitable for tests that consider biodegradation. The research can be used as a reference toward improving the simplicity and accuracy of MSW tests.

Solar energy has become a viable alternative energy because it is a clean type of energy that converts solar radiation into heat energy for various applications such as heating water, power generation, cooking, and food drying. The solar dryer, integrated with the heat energy storage system, uses nitrate salt as a heat storage medium which was designed and tested by drying 1000 grams of red pepper at 19.6 to 62.4°C. The average ambient temperature ranged from 19.3 to 37.4°C, and the maximum temperature of the heat storage media ranged from 87.8 to 125°C. The solar drying process was compared to open sun drying system loaded with 1000 grams of red pepper. The findings showed that the solar dryer maintained color and flavor and lowered the original moisture content from 86% to 10% for 24 hours compared to 36 hours of drying in open air. In this study, nitrate salt is shown to be the perfect heat storage medium for drying food products; it preserved heat for about 4 hours when there is no active sunlight.

A fault detection, isolation, and estimation approach is proposed in this paper based on Interactive Multimodel (IMM) fusion filtering and Strong Tracking Filtering (STF) for asynchronous multisensors dynamic systems. Time-varying fault is considered and a candidate fault model is built by augmenting the unknown fault amplitude directly into the system state for each kind of possible fault mode. By doing this, the dilemma of predetermining the fault extent as model design parameters in traditional IMM-based approaches is avoided. After that, the time-varying fault amplitude is estimated based on STF using its strong ability to track abrupt changes and robustness against model uncertainties. Through fusing information from multiple sensors, the performance of fault detection, isolation, and estimation is approved. Finally, a numerical simulation is performed to demonstrate the feasibility and effectiveness of the proposed method.

In Europe, the total amount of Glass Reinforced Plastic (GRP) waste is increasing. In order to valorise GRP dust (GRPd) waste and to reduce the consumption of nonrenewable resources in building materials, GRPd has been already investigated in cementitious materials where it gives even an improvement in some performances of the final products. Valorisation of GRPd waste in the production of bricks can be considered as a further alternative. In this paper, GRPd waste was substituted to the clay volume at 5% and 10% for the manufacturing of fired clay bricks. All specimens were subjected to a firing temperature of 850°C for 6 hours, then tested and compared in terms of porosity, compressive and flexural strengths, density, and water absorption. Despite a decrease in compressive strength up to 46% with 10% of GRPd substitution and an increase of water absorption from 14% to 29% with 5% and 10% of GRPd substitution, respectively, an increase in terms of lightness (about 10%), maximum flexural strength (up to 31%), and deflections at the maximum load (up to 130%) has been registered by specimens with 10% of GRPd substitution.

Over the years, the organosolv pulping process has proven to be a valuable pretreatment method for various lignocellulosic feedstocks. The objective of this study was to characterize and assess the potential applicability of the organosolv lignin fraction from European larch sawdust, as no research has been conducted in this field so far. Eight different samples were prepared from the European larch sawdust under varied reaction conditions and one milled wood lignin sample as reference. The reaction temperature and sulfuric acid loading were varied between 420 and 460 K and 0.00 and 1.10% (w/w on dry wood basis) H2SO4, respectively. The antiradical potential (via DPPH• method), chemical structure (via ATR-FTIR, 1H NMR, 31P NMR, and thioacidolysis), as well as the molecular weight distribution of the isolated lignins were analyzed and compared. Results from thioacidolysis show a direct correlation between the amount of β-ether bonds broken and pulping process severity. Similarly, both antiradical potential and phenolic hydroxyl group content exhibit a direct relationship to reaction temperature and catalyst loading. On the contrary, the content of aliphatic hydroxyl groups and the average molecular weights both decreased with increasing process severity. The high content of phenolic hydroxyl groups and antioxidative potential of the larch organosolv fractions, especially for the sample isolated at 460 K and 1.10% H2SO4 loading, indicate good applicability as antioxidants as well as feedstocks for further downstream valorization and require additional research in this area.

Construction and demolition waste has dramatically increased in the last decade, and most of it goes into landfills, increasing the burden on landfill loading and operations. Recycling of concrete is needed from the viewpoints of environmental preservation and effective utilization of resources. Regarding the durability of concrete, chloride diffusion, which is one parameter that reflects the durability of concrete, is tested in this study. Concrete made with different percentages of recycled aggregate (0%–100%, with increments of 10%) is investigated using mechanical and nondestructive testing of mixes consisting of two aggregate particle sizes (1/2″ and 3/8″). In addition, we studied the chloride diffusion of saturated concrete made with different percentages of recycled aggregate. The samples were exposed to sea water with 3% chloride concentration and tested after 2 and 4 weeks of exposure. The results indicate that the density and air content of new concrete decreased with an increase in recycled aggregates content. Compressive strength decreased with the increase in the recycled aggregate content, and a concrete mix with 40% recycled aggregate exhibited the best strength. Concrete mix with 30% recycled aggregate had the lowest chloride penetration after 2 weeks of saturation and performed better than a concrete mix with 100% natural aggregate. Owing to the lower density and higher water absorption of recycled aggregates, chloride ion diffusion increased with increasing recycled aggregate content beyond 2 weeks.

Nitrobenzene is widely produced via benzene nitration to be applied in several industries such as pharmaceutical, textile, and agricultural. In this work, an exergy sensibility analysis was performed with the aim of identifying possible opportunities of process improvements. The irreversibilities, exergy of wastes, and efficiency were calculated per stage through exergy balance. The simulation software Aspen plus V10.1 provided the physical exergies of process streams while chemical exergies were found in literature. A sensibility analysis was also carried out in order to study the effect of efficiency of some stages (polyfunctional reaction and cooling 1) on global exergy efficiency. This analysis reveals that nitrobenzene production from benzene is an efficient process from an exergy viewpoint (88%). The total irreversibilities, total exergy of wastes, and exergy of utilities-inlet were calculated in 41,647,341.85 MJ/h, 5,537,487.3 MJ/h, and 18,137,363.71 MJ/h, respectively. The results obtained from sensibility analysis suggested that heat flow of heat exchangers HE-201, HE-303, and HE-301 could provide energy requirements for heating.

This study provided a basis for new possibilities concerning the use of the sugarcane bagasse ash as a green pozzolanic addition to the Portland cement composite. To that effect, a simple micronization method using air jet milling without any other additional thermal procedure was used to control the characteristics of ash particles. This procedure not only maintains the required characteristics of the residues but can also improve some of them. Sugarcane bagasse ash is a residue produced on large scale in Brazil by ethanol and sugar plants as a result of the burning of sugarcane bagasse in energy cogeneration. The residue used in this study was initially characterized by scanning electron microscopy, granulometric and specific mass analyses, N2 adsorption measurements, X-ray diffraction, X-ray fluorescence spectroscopy, and thermogravimetric analysis with differential thermal analysis. Pozzolanic ash activity was evaluated according to the axial compressive strength at 28 days and the modified Chapelle methods. The results showed that the milling fly sugarcane bagasse ash samples presented satisfactory pozzolanic activity.

Design of treatment plants for faecal sludge management systems relies on a comprehensive accurate knowledge of FS (faecal sludge) characteristics, but this information is lacking. Developing countries like Ghana, where large proportion of the urban population (Accra) rely on onsite sanitation systems, face a lot of FSM (faecal sludge management) design challenges as a result of lack of a comprehensive study data on physicochemical characteristics of raw faecal sludge after primary dewatering. Achieving a fully operational FSM chain would imply a well understanding of the characteristics of the FS and its dynamics after primary dewatering. A study was carried out to determine the characteristics of faecal sludge brought to the Lavender Hill treatment plant, Accra Metropolis, and environs to ensure the treatability and uses of the products after treatment. The treatment plant receives an average of 150 trucks (1350m3) a day with 58% coming from private homes and 42% from public toilets. Composite samples were made from both public and private toilets facilities. Samples were taken from a reservoir holding faecal sludge from both public and private facilities, examined on daily basis and characterized. The values obtained showed high concentrations of BOD and COD values. The COD: BOD ratios showed that the faecal sludge is not stabilized yet and can be further degraded. The calorific value for the dry sludge was found to be 15.16-15.82 MJ/kg and 16.39–18.31 MJ/kg for the wet sludge. The calorific value of the sludge is adequate enough to be used as potential feedstock for green energy generation. The high concentrations of COD and organic matter of the faecal sludge make it suitable enough for biogas generation. A good correlation (r=0.909,R2=82.6%) between the calorific value and the TVS was found to be CV=0.122TVS+7.44. Heavy metal concentrations were low and satisfied the EPA Ghana guidelines for sludge. Thus products from the treatment can be used for agricultural purposes.

This paper compares stiffness degradation models of cross-ply glass fiber/epoxy laminates based on four of the most commonly used approaches to micromechanical modelling: shear-lag, variational, McCartney, and synergistic damage mechanics (SDM). All of these include the process of defining 0/90s laminate unit cell, from which governing differential equations and corresponding boundary conditions are stated. Afterwards, these boundary value problems (BVP) are solved in order to obtain a stress function which couples the initial and perturbation stresses, the latter being in function of crack density, thus related to material stiffness reduction. When compared against experimental results, shear-lag model presented accurate results however, additional differentiation and integration steps were required in order to obtain the final stress field. Hashin’s variational method predicts correctly the boundary conditions at crack surfaces and gives out the complete stress field. McCartney’s approach shows further improvement over the previous two models, taking into account thermal strains and stresses. Finally, SDM, which is designed for numerical experimentation, implying a more economical alternative in comparison to traditional physical experimentation, also presented very good agreement with experimental results and can be extended to arbitrary laminate stackings, going beyond the classical cross-ply.

The immobilization of cellulases could be an economical alternative for cost reduction of enzyme application. The derivatives obtained in the immobilization derivatives were evaluated in recycles of paper filter hydrolysis. The immobilization process showed that the enzyme recycles were influenced by the shape (drop or sheet) and type of the mixture. The enzyme was recycled 28 times for sheets E′ and 13 times for drops B′. The derivative E′ showed the highest stability in the recycle obtaining 0.05 FPU/g, RA of 10%, and FPU Yield of 1.64 times, higher than FPU spent or Net FPU Yield of 5.3 times, saving more active enzymes. The derivative B showed stability in recycles reaching 0.15 FPU/g of derivative, yield of Recovered Activity (RA) of 25%, and FPU Yield of 1.57 times, higher than FPU spent on immobilization or Net PFU Yield of 2.81 times. The latex increased stability and resistance of the drops but did not improve the FPU/gram of derivative.

The production and nature of the biocrude obtained from Spirulina sp. by hydrothermal liquefaction (HTL) technology is focused in this investigation. Our aim is to evaluate the interaction of different factors on the bio-oil production through HTL using microalgae that contains relatively low lipid content and high protein. Optimization of three key parameters—concentration (mass of algae per mass of solvent), reaction temperature, and holding time—was carried out by response surface methodology (RSM). In this work, we used central composite design to conduct the experiment process. Graphical response surface and contour plots were used to locate the optimum point. The final results showed that the optimum concentration, temperature, and holding time were 10.5%, 357°C, and 37 min, respectively. Under the optimum conditions established, yield of the biocrude (41.6 ± 2.2%) was experimentally obtained using the fresh microalgae. This study showed the potential of bio-oil production of Spirulina sp. by HTL technology, but it still needs more improvement of the biocrude for utilization.

Sugarcane press mud (SPM) has a high potential to produce renewable energy through anaerobic digestion (AD); however, hydrolysis is the limiting stage of the process due to the presence of slowly biodegradable compounds. An alternative that can improve this deficiency is anaerobic codigestion (AcoD). In this investigation, the monodigestion of SPM and its AcoD with food waste (FW) were evaluated through the biochemical methane potential (BMP) test, and kinetic parameters were analyzed through the analysis of the kinetic models of first order and modified Gompertz. This study showed that the AcoD of SPM with FW improved the hydrolysis stage, increased methane (CH4) yield, improved the stability of the process, and presented synergistic effects. As regards the hydrolysis stage, the hydrolysis constant was increased, and the lag phase was reduced. The monodigestion of SPM (SPM : FW 100 : 0) showed an increase of 9% with the addition of external nutrients solution, while that of AcoD in the SPM : FW 80 : 20 ratio showed the highest CH4 yield, with increments of 12 and 22% in comparison with the monodigestion of SPM under WN and NN conditions, respectively. It is even possible to add up to 40% of FW (SPM : FW 60 : 40) and achieve an increase of 5% compared to the monodigestion of SPM under the NN condition. The synergistic effects obtained in this study showed that the incorporation of FW, in the substrates ratios evaluated, would improve the AD of the SPM without addition of external nutrients solution, which represents economic and environmental benefits of implementing this alternative at full scale.

Piggery wastewater is a kind of high concentration organic wastewater with high concentration of pollutants, large amount of emissions, and serious environmental pollution and is difficult to deal with. Piggery wastewater was treated with autothermal hyperthermia aerobic digestion process (ATAD) and its biodegradation kinetics was studied. The ATAD system was automatically heated up and the reaction temperature rose from ambient temperature of 20°C to a maximum temperature of 64°C. Based on Arrhenius formula, the empirical model is obtained through dimensional analysis. The removal of volatile suspended solids (VSS) was correlated with the initial VSS concentration, water inlet temperature, aeration rate, and agitation rate in the model. In the empirical model, the apparent activation energy was 2.827 kJ·mol−1. The exponentials for the initial VSS concentration, aeration rate, and stirring rate were 1.0587, −0.0976, and −0.1618, respectively. The correlation coefficient of the exponential factor was 0.9971. The VSS removal efficiency predicted by the model was validated with an actual test, showing a maximum relative deviation of 8.82%. Sludge systems show a lower diversity of microbial populations and Bacillus occupies a very important position in the reactor. The data obtained will be useful for optimizing piggery wastewater treatment process. The new model provided good theoretical guidance with good practicality.

This research focuses on developing a mix design methodology for alkali-activated high-calcium fly ash concrete (AAHFAC). High-calcium fly ash (FA) from the Mae Moh power plant in northern Thailand was used as a starting material. Sodium hydroxide and sodium silicate were used as alkaline activator solutions (AAS). Many parameters, namely, NaOH concentration, alkaline activator solution-to-fly ash (AAS/FA) ratio, and coarse aggregate size, were investigated. The 28-day compressive strength was tested to validate the mix design proposed. The mix design methodology of the proposed AAHFAC mixes was given step by step, and it was modified from ACI standards. Test results showed that the 28-day compressive strength of 15–35 MPa was obtained. After modifying mix design of the AAHFAC mixes by updating the AAS/FA ratio from laboratory experiments, it was found that they met the strength requirement.

The anaerobic batch test (45 days at 37°C) was performed to describe the effect of thermal pretreatment at moderate temperatures (60, 80, and 100°C) over durations of 10 and 20 minutes on the enhancement of biogas production using hotel food waste from city of Jaipur, India. The results showed that the total cumulative biogas production with thermal pretreatment (100°C, 10 minutes) was 41% higher than the control. Also, this alternative gets first rank using multicriteria decision making model, VIKOR. This outcome was obtained due to the enhancement of degradation of organic compounds such as protein and volatile solids that occurred in the linear trend. Modified Gompertz and Logistic models were used to study the effect of different pretreatment parameters on lag time and biogas yield. Scanning electron microscopy and Fourier transform infrared spectroscopy were also employed to investigate the effect of thermal pretreatment on the physiochemical properties of food waste.

The removal of pollutants from textile wastewater via electrochemical oxidation and a coupled system electrooxidation—Salix babylonica, using boron-doped diamond electrodes was evaluated. Under optimal conditions of pH 5.23 and 3.5 mA·cm−2 of current density, the electrochemical method yields an effective reduction of chemical oxygen demand by 41.95%, biochemical oxygen demand by 83.33%, color by 60.83%, and turbidity by 26.53% at 300 minutes of treatment. The raw and treated wastewater was characterized by infrared spectroscopy to confirm the degradation of pollutants. The wastewater was oxidized at 15-minute intervals for one hour and was placed in contact with willow plants for 15 days. The coupled system yielded a reduction of the chemical oxygen demand by 14%, color by 85%, and turbidity by 93%. The best efficiency for the coupled system was achieved at 60 minutes, at which time the plants achieved more biomass and photosynthetic pigments.

The purpose of this study was to evaluate the efficiency of removal of suspended solids in terms of turbidity, color, and chemical oxygen demand (COD) when integrating the electrocoagulation process using aluminum sacrificial anodes and the sand filtration process as a pretreatment of wastewater from the chocolate manufacturing plant in Toluca, México. Wastewater from the chocolate manufacturing industry used in this study is classified as nontoxic, but is characterized as having a high content of color (5952 ± 76 Pt-Co), turbidity (1648 ± 49 FAU), and COD (3608 ± 250 mg/L). Therefore, enhanced performance could be achieved by combining pretreatment techniques to increase the efficiencies of the physical, chemical, and biological treatments. In the integrated process, there was a turbidity reduction of 96.1 ± 0.2% and an increase in dissolved oxygen from 3.8 ± 0.05 mg/L (inlet sand filtration) to 6.05 ± 0.03 mg/L (outlet sand filtration) after 120 min of treatment. These results indicate good water quality necessary for all forms of elemental life. Color and COD removals were 98.2 ± 0.2% and 39.02 ± 2.2%, respectively, during the electrocoagulation process (0.2915 mA/cm2 current density and 120 min of treatment). The proposed integrated process could be an attractive alternative of pretreatment of real wastewater to increase water quality of conventional treatments.

Carbon-containing pellets were prepared with the carbonized product of agricultural wastes and iron concentrate, and an experimental study on the direct reduction was carried out. The experimental results demonstrated that carbon-containing pellets could be rapidly reduced at 1200 to 1300°C in 15 minutes, and the proper holding time at high temperature was 15 to 20 min. The degree of reduction gradually increased with temperature rising, and the appropriate temperature of reducing pellets was 1200°C. The weight loss rate and reduction degree of pellets increased with the rise of carbon proportion, and the relatively reasonable mole ratio of carbon to oxygen was 0.9. A higher content of carbon and an appropriate content of volatile matters in biomass char were beneficial to the reduction of pellets. The carbon-containing pellets could be reduced at high speeds in the air, but there was some reoxidization phenomenon.