Removal Yield Research Articles

RESEARCH OF THE PROCESS OF EXTRACTION OF BLACK CUMIN OIL WITH PRELIMINARY HEAT TREATMENT

The aim of the study is to increase the yield of oil from black cumin seeds. The results of studies of the influence of technological parameters - temperature and duration of drying of black cumin seeds on indicators of the yield of oil, cake and moisture removal from seeds are presented. The optimal technological parameters of the influence of the preliminary heat treatment process on the indicators of the maximum oil yield, acid number, color, and oil moisture have been established. The variable parameters were the temperature from 80 to 130 °C and the duration of the heat treatment process from 5 to 60 minutes. The possibility of increasing the oil yield by 6,11% has been shown. For this, the drying process must be carried out at a temperature of 100 °C and a process duration of 15 minutes. At the same time, the degree of oil extraction increases from 59,13% to 75,24%, the acid number decreases to 2,98, humidity to 0,12%, and color to 40.

Preparation of Tin–Antimony anode modified with carbon nanotubes for electrochemical treatment of coking wastewater

To improve the electrocatalytic activity, carbon nanotubes (CNTs) were used to modify a titanium-supported tin–antimony anode (Ti/SnO2–Sb). Compared to a Ti/SnO2–Sb anode, the Ti/SnO2–Sb-CNTs anode exhibited a higher oxygen evolution potential (1.62 V), smaller crystalline volume (71.23 Å3), larger active surface area (0.371 mC cm−2), lower charge transfer resistance (8.24 Ω), and longer service life (291 h). The CNTs provided the Ti/SnO2–Sb anode with effective electrocatalytic activity, conductivity and stability. To evaluate its performance, the Ti/SnO2–Sb-CNTs anode was utilized for the treatment of coking wastewater. The chemical oxygen demand (COD) and total organic carbon (TOC) removal yields of the coking wastewater reached 83.05% and 74.56% under the optimal current density of 25 mA m−2, Na2SO4 concentration of 35 mM, and plate spacing of 10 mm. UV254, ultraviolet–visible absorption spectroscopy, excitation–emission matrix spectra spectroscopy, and Fourier-transform infrared spectroscopy analyses showed that the aromatic and nitrogenous compounds in the coking wastewater were degraded. Furthermore, the electrochemical treatment could effectively reduce the toxicity of the coking wastewater. The energy consumption of the coking wastewater treatment was reduced to 396.56 kWh (kg COD)−1. This study provides a basis engineering application of the electrochemical oxidation of coking wastewater.

Efficiencies of anaerobic hybrid and UASB reactors to alleviate the adverse effect of elevated salinity in wastewater

AbstractBACKGROUNDUntreated high‐strength salinity wastewaters pose a serious threat to the environment. Anaerobic treatment is an effective process with double advantages of waste stabilization and energy production. However, high organic compound and sodium toxicity in high‐salinity wastewaters adversely affect the performance of anaerobic treatment. In this study, anaerobic hybrid (AH) and upflow anaerobic sludge blanket (UASB) reactors were investigated for their efficiencies to alleviate the negative effects of high‐salinity wastewater.RESULTSDouble increases in the NaCl concentration drastically deteriorated the performances of both reactors. The activities of acetoclastic methanogens (ACM) and hydrogenotrophic methanogens (HTM) in both reactors decreased to 22–28% and 36–40% compared to the previous period, respectively. However, the methanogen population (Methanosarcinales and Methanobacteriales) was not affected negatively. The AH reactor exhibited excellent performance during the recovery and restart periods, which only required 7 days to complete the recovery period. Furthermore, during the restart period, the AH reactor showed high chemical oxygen demand (COD) removal efficiency, methane (CH4) production and yield as ≈90%, 2600 mL day−1 and 0.30 m3 CH4 kg−1 CODremoved, respectively. The rate of biomass washout from the AH reactor also was lower compared to the UASB reactor. The concentration of attached biomass in the packed zone of the AH reactor gradually increased indicating the growth of an active microbial biofilm.CONCLUSIONThe excellent performance of the AH reactor was presumably a result of its packed zone configuration which provided the supporting media to entrap smaller microbial aggregates, reduce biomass washout and support the growth of active biofilm. © 2021 Society of Chemical Industry (SCI).

Partial Nitrification in a Sequencing Moving Bed Biofilm Reactor (SMBBR) with Zeolite as Biomass Carrier: Effect of Sulfide Pulses and Organic Matter Presence

This work aimed to achieve partial nitrification (PN) in a Sequencing Moving Bed Biofilm Reactor SMBBR with zeolite as a biomass carrier by using sulfide pulses in the presence of organic matter as an inhibitor. Two conditions were evaluated: sulfide (HS−) = 5 mg S/L and vvm (air volume per liquid volume per minute, L of air L−1 of liquid min−1) = 0.1 (condition 1); and a HS− = 10 mg S/L and a vvm = 0.5 (condition 2). The simultaneous effect of organic matter and sulfide was evaluated at a Chemical Oxygen Demand (COD) = 350 mg/L and HS− = 5 mg S/L, with a vvm = 0.5. As a result, using the sulfide pulse improved the nitrite accumulation in both systems. However, Total Ammonia Nitrogen (TAN) oxidation in both processes decreased by up to 60%. The simultaneous presence of COD and sulfide significantly reduced the TAN and nitrite oxidation, with a COD removal yield of 80% and sulfide oxidation close to 20%. Thus, the use of a sulfide pulse enabled PN in a SMBBR with zeolite. Organic matter, together with the sulfide pulse, almost completely inhibited the nitrification process despite using zeolite.

Mechanisms of heavy metal and oil removal from synthetic saline oilfield produced water by electrocoagulation

In the present study, an electrocoagulation process was applied to treat saline oilfield-produced water. The kinetics of simultaneous heavy metal and oil removal in the saline environment under different conditions including four-electrode materials of copper, zinc, iron, and aluminum, aeration and agitation rate, oil content, and salinity was investigated. The nature of the electro-generated species and possible abatement mechanisms were explored and compared by using FE-SEM/EDS, FTIR, XRD, and BET analyses. At low and high salinities, cadmium adsorption followed Langmuir and Freundlich models, suggesting the transformation of identical adsorption sites to heterogeneous ones. Cadmium removal efficiencies of 99/73% were obtained at low/high salinity with iron and 99.9 and 82% using copper and zinc electrodes in a saline environment. The cadmium adsorption capacity of different anode materials exhibited the order of copper > zinc > iron > aluminum. The adsorption capacity was considerably reduced in saline condition due to more crystalline structure and lower surface area and porosity of the particles while it was enhanced by the oil, caused by structural changes including more uniform pores, the elevated surface area, and porosity. The COD removal yield of 89% for low salinity and 80/73% at high salinity with/without aeration were achieved by iron. The highest COD removal yield of about 95% was achieved by the aluminum electrodes, compared to 85 and 87% for copper and zinc electrodes. The main removal mechanisms were outer- and inner-sphere complexation, and surface precipitation.

Modeling uranium (II) removal from aqueous solution by micellar enhanced ultrafiltration using response surface methodology

In this study, response surface methodology has been used to model and optimize the flux and the removal efficiency of uranium from aqueous solution via micellar enhanced ultrafiltration (MEUF) using Sodium dodecyl sulfate (SDS) as a surfactant. Screening study was employed and as a result, pH, pressure, uranium concentration and SDS concentration was obtained as the effective factors on the process. Analysis of variance (ANOVA) illustrated that quadratic model was highly significant. Furthermore, a central composite design (CCD) by use of response surface methodology (RSM) was applied to obtain the reciprocal interactions between the variables and optimizing them. As a result of optimizing, the maximum rejection coefficient of uranium was found more than 0.65 in SDS concentrations greater than its critical micelle concentration (CMC) which was achieved as 16 mM using solution conductivity measurements. While SDS concentration was below its critical micelle concentration, maximum rejection of uranium was 0.15. This demonstrates a good growth in uranium removal yield.

Removal of Phenols in Table Olive Processing Wastewater by Using a Mixed Inoculum of Candida boidinii and Bacillus pumilus: Effects of Inoculation Dynamics, Temperature, pH, and Effluent Age on the Abatement Efficiency.

The main goal of this paper was to assess the ability of a combination of Candida boidinii and Bacillus pumilus to remove phenol in table olive processing water, as a function of some variables, like temperature, pH, a dilution of waste and the order of inoculation of the two microorganisms. At this purpose C. boidinii and B. pumilus were sequentially inoculated in two types of table olive processing water (fresh wastewater, FTOPW and wastewater stored for 3 months-aged wastewater, ATOPW). pH (6 and 9), temperature (10 and 35 °C) and dilution ratio (0, 1:1) were combined through a 2k fractional design. Data were modeled using two different approaches: Multifactorial Analysis of Variance (MANOVA) and multiple regression. A higher removal yield was achieved by inoculating B. pumilus prior to the yeast (192 vs. 127 mg/L); moreover, an increased efficiency was gained at 35 °C (mean removal of 200 mg/L). The use of two statistic approach suggested a different weight of variables; temperature was a global variable, that is a factor able to affect the yield of the process in all conditions. On the other hand, an alkaline pH could increase the removal of phenol at 10 °C (25–43%).

Synergistic effects of hydrothermal and deep eutectic solvent pretreatment on co-production of xylo-oligosaccharides and enzymatic hydrolysis of poplar

Full utilization of lignocellulose is critical for its biorefinery development. In this study, a sustainable biorefinery process based upon poplar sawdust was established using sequential hydrothermal and deep eutectic solvent treatment (HP-DES). Results showed that single hydrothermal pretreatment (HP) could produce 53.2% xylo-oligosaccharides (XOS) (based on raw xylan), while the enzymatic digestibility was low. Conversely, single DES treatment achieved effective enzymatic digestibility but low XOS yields. As compared to HP, both DES treatment and HP-DES showed high selectivity for lignin removal and high glucose yield. Surprisingly, most of HP-DES residues had obviously lower enzymatic digestibilities than those of single DES residues. This was mainly explained by the differences of the surface lignin contents between DES and HP-DES residues. Moreover, nearly complete enzymatic hydrolysis of HP-DES residues was achieved with the addition of bovine serum albumin. This work demonstrated this HP-DES yielded XOS, fermentable sugar, and pure lignin with high processibility.

Mushroom-mediated delignification of agricultural wastes for bio-ethanol production

Biological pretreatment is a cost-effective method of delignifying lignocellulosic biomass, making it less recalcitrant to hydrolysis into fermentable sugars. In this study, selected agricultural wastes were pretreated with mushrooms (Lentinus squarrosulus and Pleurotus ostreatus) to delignify them for bioethanol production. The substrates were supplemented with 0.2 % CaCO3, inoculated with 12 % (w/w) L. squarrosulus and Pleurotus ostreatus spawns and incubated at 25 oC for 21 days. The highest lignin removal and highest bioethanol yield of 77.45 % and 13.98 % were obtained from bean husks pretreated with L. squarrosulus. Similarly, 64.29 % and 60.92 % lignin were removed from the Pleurotus ostreatus-pretreated banana leaves and sawdust, respectively, while 12.08 % and 13.05 % bio-ethanol yields were recorded, respectively. These findings demonstrate that affordable and straightforward mushroom delignification of abundant and cheap biomass can improve hydrolysis outcomes, thus easing bioethanol production.

Bone meal and chitosan biocomposite: a new biosorbent for the removal of Victoria Blue R from wastewater

Chitosan immobilized bone meal (CIBM) was prepared as a biosorbent and Victoria Blue R (VBR) textile dyestuff was removed from wastewater using CIBM via biosorption. For this purpose; the effect of pH, contact time, ionic strength, temperature, biosorbent amount, and initial sorbate concentration were studied in the batch system. The specific surface area, surface morphology and functional groups of CIBM were characterized using BET, SEM and FTIR techniques. In the preliminary biosorption studies with pure bone meal, the removal yield of VBR from solutions of 25 mg/L VBR prepared in pure water was found to be 40.32%, while after modification with chitosan, a removal yield of 98.69% was achieved. As a result, it was observed that the biosorption efficiency increased significantly via modification. The biosorption equilibrium was set at the original pH of the dye with a biosorbent amount of 3.00 g/L in 15 min., which are the optimum adsorption parameters of the batch biosorption process. The removal of VBR from real wastewater was investigated, and the efficiency was found to be 90.40%. Biosorption-desorption cycle was investigated for 11 cycles, and CIBM almost maintained its biosorption capacity until the ninth cycle. Kinetic, isotherm and thermodynamic models were used to analyze the data obtained from the experiments. As kinetic models, pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models were used along with the intraparticle diffusion model. For isotherm models, Langmuir, Freundlich, and Dubinin–Radushkevich (D-R) models were employed. It was determined that the experimental biosorption data obey the second-order kinetic model.

Electrocoagulation and electro fenton and their applications in the processing of lindi water from landfill waste in campus area of Diponegoro University

Piles of garbage could an impact on reducing aesthethics, lowering the quality of groundwater and the health of the people who live around the landfill (TPA). The focus of research aims to reduce the content of organic pollutants dissolved in leachate at the Diponegoro University landfill (TPA). There are 2 methods chosen, namely the electrocoagulation method and the Fenton electro method. The electrodes used in these 2 methods are the same, namely aluminum and ferrous metals (as anode) and carbon (as cathodes). Our observations in the laboratory show that the dissolved organic matter in leachate at Diponegoro University’s final disposal site (TPA) (COD parameter) was 6.2 ppm, still far below the leachate content of TPA Jati barang 9.1 -16.2 ppm. The limit of the Government of the Republic of Indonesia in PP 82, 2001 (10 ppm). With the electrocoagulation method, when aluminum metal (as anode) was used, the amount of organic material that could be removed was 77.6%, while with ferrous metal (as anode) the amount of organic material that could be removed was smaller, namely 69.8%. Whereas with the Fenton electro method, when using aluminum metal (as anode), the amount of organic material that could be removed was 89.9%, while with ferrous metal (as anode) the amount of organic material that could be removed was smaller, namely 71.6%. The addition of inorganic salts (100 ppm NaCl and 100 ppm Na2SO4) was able to increase the yield of organic matter removal between 2.1 - 5.1%.

Role of the lactobacilli in food bio-decontamination: Friends with benefits

Food contamination such as toxins and heavy metals has been increasing in the last few decades as a result of industrialization in general and as part of food production in particular. Application of microorganisms in toxins and heavy metals bio-removal has been documented and applied as a favorable decontamination approach due to being environmentally friendly, reasonably simple, and economically feasible. Lactobacilli have been proposed and applied as a beneficial biologic sorbent for toxins and heavy metals in processes of reducing their hazardous bio-availability. The purpose of this review is to summarize the known role of Lactobacillus bacterial species in food bio-decontamination processes. After a quick glimpse of the worthy properties of lactobacilli, their cell wall structure is mentioned. Then the potential role of Lactobacillus strains for mycotoxins (aflatoxins, patulin, ochratoxin A, fumonisins, zearalenone, cyanotoxins, and trichothecenes) and heavy metals (lead, arsenic copper, mercury, cadmium, zinc, aluminum, chromium, and iron) bio-removal were described. In addition, the role of various factors in removal yield and the decontamination mechanism were explained. Finally, the lactobacilli-contaminant stability, in vivo studies, and being a friend or foe of Lactobacillus bacteria are discussed.

Exhaustion of pentachlorophenol in soil microcosms with three Pseudomonas species as detoxification agents.

Pentachlorophenol (PCP) is a toxic compound, which is widely used as a wood preservative product and general biocide. It is persistent in the environment and has been classified as a persistent organic pollutant to be reclaimed in many countries. Bioremediation is an emerging approach to rehabilitating areas polluted by recalcitrant xenobiotics. In the present study, we evaluated the potential of three strains of Pseudomonas (P. putida S121, P. rhizophila S211, and P. fuscovagiceae S115) as bioremediation agents in depletion and detoxification of PCP in soil microcosms. PCP removal was effectively optimized using a central-composite experimental design and response surface methodology (RSM). The optimum conditions for maximum PCP removal yield (85 ± 5%) were: 500mg/kg PCP concentration, 108 UFC/g soil inoculum size of each strain and 55days incubation period. The bacterial strains, P. putida, P. rhizophila, and P. fuscovagiceae, showed good capability to tolerate and degrade PCP so that they could be successfully used in synergistic effect to treat PCP polluted soils.

Adsorption of micropollutants onto realistic microplastics: Role of microplastic nature, size, age, and NOM fouling

This work aims at evaluating the role of nature, size, age, and natural organic matter (NOM) fouling of realistic microplastics (MPs) on the adsorption of two persistent micropollutants (diclofenac (DCF) and metronidazole (MNZ)). For such goal, four representative polymer types (polystyrene (PS), polyethylene terephthalate (PET), polypropylene (PP) and high-density polyethylene (HDPE)) were tested. MPs were obtained by cryogenic milling of different commercial materials (disposable bottles, containers, and trays), and fully characterized (optical microscopic and SEM images, FTIR, elemental analysis, water contact angle and pHslurry). The micropollutants hydrophobicity determined to a high extent their removal yield from water. Regardless of the MP's nature, the adsorption capacity for DCF was considerably higher than the achieved for MNZ, which can be related to its stronger hydrophobic properties and aromatic character. In fact, aromatic MPs (PS and PET) showed the highest adsorption capacity values with DCF (~100 μg g−1). The MP size also played a key role on its adsorption capacity, which was found to increase with decreasing the particle size (20–1000 μm). MPs aging (simulated by Fenton oxidation) led also to substantial changes on their sorption behavior. Oxidized MPs exhibited acidic surface properties which led to a strong decrease on the adsorption of the hydrophobic micropollutant (DCF) but to an increase with the hydrophilic one (MNZ). NOM fouling (WWTP effluent, river water, humic acid solution) led to a dramatic decrease on the MPs sorption capacity due to sorption sites blocking. Finally, the increase of pH or salinity of the aqueous medium increased the micropollutants desorption.

Treatment of Wastewaters from the Olive Mill Industry Wastewaters by Sonication Process at Different Conditions

In this study, the effects of increasing sonication time (60 min, 120 and 150 min), increasing temperatures (25oC, 30oC and 60oC), different Dissolved Oxygen (DO) concentrations (2 mg/l, 4 mg/l, 6 and 10 mg/l), different N2(g) sparging (15 and 30 min) and H2O2 concentrations (100 mg/l, 500 and 2000 mg/l) was investigated on Olive Mill Industry wastewaters (OMI ww) by sonication process. The maximum removal efficiencies were 60.91% CODdis, 59.28% TOC, 49.70% color, 58.25% total phenol, 63.27% total aromatic amines (TAAs), 37.51% total fatty acids (TFAs), at 25oC and 150 min, respectively. The maximum removal yields were 66.83% CODdis, 65.92% TOC, 83.77% color, 61.24% total phenol, 70.52% TAAs, 48.84% TFAs, at 60oC and 150 min, respectively. The maximum removal efficiencies were 88.73% CODdis, 93.79% color, 91.38% total phenol, 91.58% TAAs, 74.44% TFAs, at DO=10 mg/l, at 60oC and 150 min, respectively. The maximum removal efficiencies were 84.51% CODdis, 91.88% color, 78.98% total phenol, 74.56% TAAs, 80.18% TFAs, at 30 min N2(g) sparging, at 60oC and 150 min, respectively. The maximum removal yields were 91.13% CODdis, 93.59% color, 93.65% total phenol, 83.68% TAAs, 90.30% TFAs, at 2000 mg/l H2O2, at 60oC and 150 min, respectively. Sonication at 35 kHz proved to be a viable tool for the effective removal of COD, TOC, color, total phenol, TAAs and TFAs from OMI ww, providing a cost-effective alternative for destroying and detoxifying the refractory compounds in OMI ww.

Attached culture of Gibberella fujikuroi for biocomposite sorbent production and ciprofloxacin sequestration applications

AbstractBACKGROUNDThe fluoroquinolone antibiotics in water sources are significant threats to public health, as well as the water ecosystem and water reuse. In this study, the feasibility of the biosorption of ciprofloxacin (CIP) using pine needles biomass‐Gibberella fujikuroi immobilized biocomposite (PNGFB) was promoted. It was prepared by passive cell immobilization onto the lignocellulosic matrix. The suggested biosorbent was characterized by Fourier Transform Infrared (FTIR) analysis, Scanning Electron Microscope (SEM), and zeta potential analysis. Series of batch and continuous mode experiments were conducted.RESULTSThe results of both systems showed that the PNGFB was effectively used for the treatment of CIP contamination. The maximum uptake occurred at pH 6.0, 40 min contact time, 1.0 mL min−1 flow rate, and 0.10 g (batch) and 0.20 g (column) PNGFB dosages. Redlich–Peterson isotherm model was the best suited to equilibrium data and the pseudo‐second‐order model predicted the biosorption kinetics. The maximum monolayer biosorption capability was 39.17 mg g−1. The suggested biocomposite also reached CIP removal yields of 64.14% and 53.74% in synthetic hospital effluent and synthetic urine samples containing 100 mg L−1 antibiotic, respectively. The regeneration study indicates that PNGFB retained its high biosorption and desorption yields during five cycles of the biosorption‐desorption.CONCLUSIONThe findings clearly showed that the PNGFB seems to be an eco‐friendly, effective, economic, and potentially viable biocomposite sorbent for the sustainable removal of CIP contamination. © 2021 Society of Chemical Industry (SCI).

Polyurethane sponge modified by alginate and activated carbon with abilities of oil absorption, and selective cationic and anionic dyes clean-up

In this study, compact disc-derived activated carbon black (D-ACB) was hybridized with sodium alginate to modify polyurethane (PU) sponges. After immersing the PU sponge in this suspension, it was crosslinked in the presence of CaCl2 to obtain PU@D-ACB/calcium alginate composite sponge (PU@D-ACB.CaA) so that after crosslinking, no leaching was observed. The hydrophobic nature of PU changed to superhydrophilic for treated PU, and the water contact angle decreased from 122° ± 11.8 to 0°. PU@D-ACB.CaA composite sponge showed higher mechanical properties (with a compressive strength of 1809 ± 1210 kPa and Young's modulus of 45 ± 7.1 kPa) in comparison to the neat PU (with a compressive strength of 2.84 ± 0.08 kPa and Young's modulus of 3.5 ± 0.71 kPa). The composite could absorb organic solvents and oil 8–21 times the sponge's weight, and it showed reusability properties as well. High removal yields (82% of methylene blue (MB), 97% of malachite green, and 54% of crystal violet) were attained for the composite sponge compared to the neat PU. The composite showed fast adsorption ability with 65% adsorbed MB within the first 15 min and equilibrium almost reached within 360 min, and 98% dye was removed. The outcomes presented that the linear form of Langmuir isotherm and nonlinear form of pseudo-second-order can better express MB adsorption on PU@D-ACB.CaA composite sponge. It showed the maximum adsorption capacity of 71.32 mg/g for the lower range and 386.49 mg/g for the higher range of concentrations. The composite could be reused for five cycles and even more, and the adsorption mechanisms on this sponge mostly contain physical interactions. Consequently, this study presents an economical and effective strategy for manufacturing an adsorbent containing recycled polymeric compact discs, efficiently eliminating dyes from wastewater.

Removal of phenolic compounds from de-oiled sunflower kernels by aqueous ethanol washing

Selective removal of phenolic compounds (PCs) from de-oiled sunflower kernel is generally considered a key step for food applications, but this often leads to protein loss. PC removal yield and protein loss were assessed during an aqueous or aqueous ethanol washing process with different temperatures, pH-values and ethanol contents. PC yield and protein loss increased when the ethanol content was < 60% or when a higher temperature was applied. Our main finding is that preventing protein loss should be the key objective when selecting process conditions. This can be achieved using solvents with high ethanol content. Simulation of the multi-step exhaustive process showed that process optimization is possible with additional washing steps. PC yield of 95% can be achieved with only 1% protein loss using 9 steps and 80% ethanol content at 25℃. The functional properties of the resulting concentrates were hardly altered with the use of high ethanol solvents.

Comparison between two reactors using Trametes versicolor for agricultural wastewater treatment under non-sterile condition in sequencing batch mode

Agricultural wastewater is a major source of herbicides, which pose environmental and health concerns owing to their substantial use and poor elimination rate in conventional wastewater treatment plants. White-rot fungi are versatile in degrading xenobiotics; however, the key problem encountered with their application in actual scenarios is competition with indigenous microorganisms, mainly bacteria. To address this barrier, two different strategies were implemented in the present study. One strategy was to set up a trickle bed with Trametes versicolor immobilized on pine wood, and another strategy was to employ a T. versicolor-pelleted, fluidized-bed reactor to remove diuron and bentazon from actual wastewater under non-sterile conditions. The residence time in the trickle bed was estimated using three methodologies. With 10 batches of a 3-day cycle operation, although the trickle-bed reactor possessed a shorter contact time (8.5 h per cycle) and lower laccase activity compared with those of the fluidized-bed reactor, it demonstrated a higher removal yield and lower bacterial counts. In addition, the utilization of pine wood as a carrier obviously reduced the cost since no additional nutrients were required. Hence, after evaluating all advantages and limitations of both bioreactors, for the purpose of treating over the long term and scaling up, a trickle-bed reactor is the preferred choice.

Methylene blue dye removal using Parkia speciosa pod based activated carbon

Critical environmental issues have emerged from wastewater of industrial textile effluent discharge which consists of refractory dyes. Effective methods such as activated carbon (AC) adsorption is extremely demanded for solving this environmental pollution. In this study, low-cost AC was developed from Parkia speciosa pods (PSP) using microwave-assisted activation technique for the methylene blue (MB) dye adsorption. Optimization on activating conditions in terms of MB removal and AC yield was performed using response surface methodology (RSM). The optimum microwave irradiation power (MIP) of 416.50 W was found to have significant effect on MB removal at 2 minutes activation. The Parkia speciosa pods activated carbon (PSPAC) possessed intermediate surface area and total pore volume of 51.3 m 2/g and 0.0681 cm 3/g, respectively. PSPAC surface morphology was microscopically observed with highly porous structure indicating characteristics of good AC. Batch adsorption studies with various initial concentrations discovered that MB adsorption increased with increasing initial concentrations and contact time. The experimental data was in close fit using Langmuir isotherm and followed pseudo-first-order kinetic models. The MB dye adsorption process was governed by simultaneous surface adsorption and intraparticle diffusion. The results of studies proved that PSPAC is a potential adsorbent for dye-contaminated wastewater.