Water Pretreatment Research Articles

Health risks of Cryptosporidium and Giardia in the application of surface water and septic tank effluent in Chinese agriculture: Impact on cancer patients identified by quantitative microbial risk assessment

The protozoa Cryptosporidium and Giardia are major causes of diarrhea and are commonly found on vegetables in China. They pose a health risk, particularly to immunocompromised individuals, including cancer patients. A quantitative microbial risk assessment of Chinese data evaluated the risks of Cryptosporidium and Giardia exposure arising from the application of surface water and septic tank effluent to agricultural land. Exposure via agricultural produce consumption (consumers) and agricultural practices (farmers) was considered for subpopulations of cancer patients and immunocompetent people in urban and rural areas, and risk mitigation scenarios were modelled. The cumulative disease burdens attributable to cryptosporidiosis and giardiasis were, respectively, 9.68×10−6 and 5.57×10−5 disability-adjusted life years per person per year (DALYs pppy) for immunocompetent people, and 3.14×10−5 and 1.51×10−4 DALYs pppy for cancer patients. Cancer patients were approximately three times more likely to have an individual disease burden than immunocompetent people. The disease burden was higher for consumers than farmers, and higher in rural areas than urban areas (all exceeding the maximum recommended by the World Health Organization). The highest burdens were in provinces of high population, such as Henan, Guangdong, and Sichuan, while the burden associated with human and livestock fecal effluent application was higher than with surface water irrigation. Of the three vegetables studied, lettuce posed the greatest risk, followed by bok choy, while cucumber posed the least risk. Risk mitigation scenario analysis showed that pre-treatment of surface water and feces, and appropriate post-harvest handling of vegetables, including disinfection, cooking, and adequate surface heat treatment (75 °C for 60 s), should be considered when attempting to reduce disease burdens. The methodology and findings of this study are useful for evaluating and reducing the burden of Cryptosporidium and Giardia infections associated with agricultural irrigation and fertilization practices, particularly on cancer patients.

Subcritical Water Pretreatment for the Efficient Valorization of Sorghum Distillery Residue for the Biorefinery Platform.

The depletion of fossil fuels is resulting in an increased energy crisis, which is leading the paradigm shift towards alternative energy resources to overcome the issue. Lignocellulosic biomass or agricultural residue could be utilized to produce energy fuel (bioethanol) as it can resolve the issue of energy crisis and reduce environmental pollution that occurs due to waste generation from agriculture and food industries. A huge amount of sorghum distillery residue (SDR) is produced during the Kaoliang liquor production process, which may cause environmental problems. Therefore, the SDR generated can be utilized to produce bioethanol to meet current energy demands and resolve environmental problems. Using a central composite experimental design, the SDR was subjected to hydrothermal pretreatment. The conditions selected for hydrothermal pretreatment are 155 °C, 170 °C, and 185 °C for 10, 30, and 50 min, respectively. Based on the analysis, 150 °C for 30 min conditions for SDR hydrothermal pretreatment were selected as no dehydration product (Furfural and HMF) was detected in the liquid phase. Therefore, the pretreated slurry obtained using hydrothermal pretreatment at 150 °C for 30 min was subjected to enzymatic hydrolysis at 5% solid loading and 15 FPU/gds. The saccharification yield obtained at 72 h was 75.05 ± 0.5%, and 5.33 g/L glucose concentration. This non-conventional way of enzymatic hydrolysis eliminates the separation and detoxification process, favoring the concept of an economical and easy operational strategy in terms of biorefinery.

Study of stingless bee (Heterotrigona itama) propolis using LC-MS/MS and TGA-FTIR

Propolis, especially meliponini propolis is getting more popular in the functional food market, mainly due to its pharmacological importance. The quality of propolis is largely dependent upon the extraction technology and its solvent system. The present study investigated the performance of propolis extraction from maceration with and without ultrasonic pretreatment (30 min) in both water and 20% ethanol systems. Maceration was chosen to avoid degradation of heat sensitive compounds. Ultrasonic pretreatment was introduced to enhance propolis extraction from recalcitrant raw material. The yield of propolis was 4.0-5.5%. The results found that maceration with ultrasonic pretreatment, especially in aqueous ethanol increased the phenolics (17.043 mg GA/g), tannins (5.411 mg GA/g) and flavonoids (0.83 mg Q/g) content, as well as antioxidant capacity of propolis (80% at 1 mg/mL). Mass spectral based principal component analysis revealed that solvent system had higher effect (> 30%) on the variance of propolis quality rather than extraction technology. The variance of chemical composition had also led to the difference of antioxidant capacity among propolis samples. Alcohol precipitation would remove polymeric substance from propolis which was then characterised by thermogravimetric analysis coupled with Fourier transform infrared spectrometer (TGA-FTIR) after acid hydrolysis. The substance was putatively identified as hygroscopic lignocelluloses (14.4% moisture, 36.6% hemicelluloses and celluloses, 40% lignins), and started to decompose at 203°C, involving 4 steps of degradation mechanism at the highest derivative weight of 12.09%/min.

Investigating the role and mechanism of water in E-beam modified sweet potato starch: Multi-scale structure, physicochemical properties, and in vitro digestibility

Aiming to investigate the role and mechanism of the effect of water on the structural, physicochemical, and in vitro digestible properties of starch during irradiation processing. This work used water pretreatment of sweet potato starch (12%, 25%, 50%, 75% and 100% water content) and then modification by E-beam (6, 12 and 24 kGy). The results showed that E-beam treatment preserved the polarization cross, growth rings, crystal types and FT-IR patterns of sweet potato starch. Also, E-beam induced the water molecule activation and free radical production, thus promoting starch degradation. Moreover, the short-range ordered structure, relative crystallinity, molecular weight, long-chain proportion, ΔH, viscosity and swelling power of starch decreased with increasing E-beam irradiation dose. In contrast, the short-chain proportion, solubility, and resistant starch content were improved. In addition, a synergistic effect was found between the water pretreatment and E-beam, i.e., the higher the water content of the starch, the deeper the modification by E-beam. Results obtained in this study can partially elucidate the role of water content in E-beam-modified starch and provide a basis for E-beam treatment of starch-based foods under different water levels.

Subcritical water pretreatment enhanced methane-rich biogas production from the anaerobic digestion of brewer’s spent grains

ABSTRACT This study evaluated the effectiveness of a semi-continuous flow-through subcritical water hydrolysis (SWH) pretreatment of brewer’s spent grains (BSG) for subsequent application in the anaerobic digestion (AD) process. BSG pretreatment was conducted at 160 °C and 15 MPa with a flow rate of 10 mL water min−1 and 15 g water g−1 BSG. The results revealed that SWH attacked the hemicellulose structure, releasing arabinose (46.54 mg g–1) and xylose (39.90 mg g–1) sugars, and proteins (34.89 mg g–1). The start-up of anaerobic reactors using pretreated BSG (747.71 L CH4 kg−1 TVS) increased the methane yield compared with the reactor without pretreatment (53.21 L CH4 kg−1 TVS). For the process with pretreatment, the generation of electricity (134 kWh t−1 BSG) and heat (604 MJ t−1) are responsible for the mitigation of 43.90 kg CO2 eq t−1 BSG. The adoption of SWH as an eco-friendly pretreatment of biomass for AD could be a technological route to increase methane-rich biogas and bioenergy production, supporting the circular economy transition by reducing the carbon footprint of the beer industry.

Scale-up of hydrothermal processing: Liquid hot water and pilot-scale tubular steam explosion batch reactor for bioethanol production using macroalgae Sargassum spp biomass

Sargassum spp. is a biomass that can potentially use as an alternative for bioethanol production. Hydrothermal processes (liquid hot water and steam explosion pretreatment) were carried out at different operational conditions. Enzymatic hydrolysis performed a preliminary test with different ratios 1:1 and 1:2 (cellulases and hemicellulases) of enzyme loading, once selected 1:2 ratio was obtained conversion yield of 99.91% and therefore carried a scale-up in stirred bioreactor getting 95.92% saccharification yield. Pre-simultaneous saccharification and fermentation strategy was performed in a continuous stirred tank bioreactor (CSTBR), producing ethanol yield of 57.69%, and for simultaneous saccharification and fermentation strategy was performed in a bubble column reactor was 71.37% ethanol yield. The energy efficiency was analyzed in different scenarios; the best data was 30.19 (gsugar/MJ) in the bioreactor enzymatic hydrolysis process. This development allows for establishing the conditions for a third-generation biorefinery on a circular bioeconomy using Sargassum biomass.

Bio-phenolic compounds production through fast pyrolysis: Demineralizing olive pomace pretreatments

An original pathway to renewable production of phenol-rich bio-oil by fast pyrolysis of pretreated olive pomace (OP) was researched. However, inherent inorganic elements (especially alkali and alkaline earth metals) in biomass feedstocks largely modified the final bio-oil composition. To alter their catalytic activity in fast pyrolysis, different demineralisation processes (water, acid and alkali pretreatments) were employed. There was also an in-depth study of bio-oil phenolic compounds, analysing the oxygen-containing substituted groups linked to the benzene ring. From water leached samples, potassium was largely removed, enhancing the selective production of guaiacol (at room temperature) and syringol (at T = 90 ºC). Important differences were observed with HCl and HNO3 pretreatments regarding carboxylic acid and phenolic distribution. For pretreatment with NaOH, the sodium content in the sample was observed to increase to 83%. Thus, optimal phenolic selectivity (36.9%) was achieved for the alkali pretreated OP sample, where guaiacol (5.9%) and vinyl guaiacol (6.2%) yields increased and methyl guaiacol decreased. This study marks an efficient and clean pathway for converting agricultural waste into valuable phenolic enriched bio-oil. This could constitute a new way of obtaining these compounds by using renewable agriculture biomass.

Structure and Properties of Lignin Extracted from Cotton Stalk by Non-polluting Ethanol-Assisted Hot Water Pretreatment and its High-Value Utilization for Methylene Blue Removal

Structure and Properties of Lignin Extracted from Cotton Stalk by Non-polluting Ethanol-Assisted Hot Water Pretreatment and its High-Value Utilization for Methylene Blue Removal

NONWOVEN DEVELOPMENT AND CHARACTERIZATION PRODUCED FROM CIGARETTE BUTTS

Abstract The aim of this study was to develop and evaluate the performance of a nonwoven (NT) with cellulosic material from cigarette butts. The NT used as a filtering medium had a diameter of 7 cm, height of 24 cm, a surface area of 528 cm2 and a total volume of 692 cm3. The NT was applied for the filtration of water from a pond. To evaluate NT performance, NT characterization, grammage, absorption capacity and permeability analyzes were performed. The results showed that NT was characterized as a microporous material and presented a good absorption performance (values in the order of 4.01 g g-1 to 4.99 g g-1), weight of 115 g m-2, permeability between 3.787 L m-² h-1 and 3.422 L m-² h-1. The NT developed showed potential for use as a filtering medium for the surface water pre-treatment. In addition to helping to reduce the negative environmental impacts caused by the residues of cigarette butts present in the environment.

Germinação de sementes e substratos para mudas de Melocactus zehntneri

ABSTRACT The populations of Melocactus zehntneri 'chapéu-de-frade' have shown an alarming decline due to the constant withdrawal of individuals from their natural areas. The low percentage of germination of M. zehntneri seeds, added to the slow growth, requires a system for commercial propagation of this species. This study aimed to test the influence of water, hydrochloric acid or acetic acid pre-treatments on seed germination and the influence of different substrates on the initial development of M. zehntneri seedlings. The seeds were immersed in deionized water, hydrochloric acid (5N) or glacial acetic acid (100%) for 10, 20, 30, 40 and 50 minutes and placed to germinate in a Petri dish containing filter paper moistened with 5 mL deionized water. The seedlings obtained from this germination (≡ 0.4 cm diameter) were cultivated on Carolina Soil® and vermiculite [2:1] substrates; Carolina Soil® and vermiculite [2:1] + drainage; medium-grained sand; medium-grained sand + drainage; medium-grained sand and organic compost [1:1]; medium-grained sand and organic compost [1:1] + drainage; and Carolina Soil® and medium-grained sand [1:1]. The highest percentage of germination was obtained with the pre-treatment by immersion in water, in the times of 10 and 30 minutes, totaling 55% of germinated seeds. Treatments with hydrochloric acid did not increase the percentage of germinated seeds, which were also close to 50%. In the test with the substrates, in Carolina Soil® there were the best rates of seedling survival after transplanting (87.5%) and seedling development performance. Treatments containing organic compost resulted in lower survival (69%) and seedling development. Seed germination and seedling development in Carolina Soil® substrate and sand proved to be an excellent alternative for the production of M. zehntneri seedlings.

Hydrothermal pretreatment optimization of hemicellulose dissolution of sugar palm starch industrial waste

Lignocellulosic biomass is a renewable source containing three main components: cellulose, hemicellulose, and lignin. The three main components can be processed into products that have high added value. Sources of lignocellulosic biomass includes wood, grass, industrial waste, and agricultural residu. Compared to other source, industrial wastes have a higher potential to be utilized without competition for other needs and assist industry in waste treatment. The production of sugar palm starch generate biomass waste which is disposed into the environment which disturbs the surrounding community and is not utilized. To utilize lignocellulosic biomass, pretreatment is a very important step. Hydrothermal is an environmentally friendly pretreatment, without using harmful chemicals in the process. The purpose of this study was to determine the level of solubility of hemicellulose in the hydrothermal pretreatment process of sugar palm starch industrial waste. The hydrothermal method used is liquid hot water with temperature and time parameters, optimization analysis using response surface methodology (RSM). The result obtained is that the liquid hot water pretreatment method is effective in dissolving the hemicellulose from the sugar palm starch industrial waste. The relationship between variables on hemiselulosa response is modeled Y = 7.7-3.04 X1 – 5.67X2 + 0.4250 X1X2 + 1.06 X1 2 + 3.61 X2 2. The optimization results showed the optimum temperature at 195.91°C for 36.725 minutes, with a hemicellulose dissolution of 81.59% and the level of desirability is 0.852.

Subcritical Water as Pretreatment Technique for Bioethanol Production from Brewer's Spent Grain within a Biorefinery Concept.

Bioeconomy and environmental issues envisage industrial by-products such as Brewer's spent grain (BSG) as renewable resources for their recycling and reuse within a biorefinery concept. This study aimed to investigate the production of bioethanol from subcritical water (subW) pretreated BSG, following the conversion of the BSG biopolymers cellulose and hemicelluloses. The subW pretreatment was performed in a batch reactor at 174 °C, during 60 min and 5% (w/v) of dry BSG charge. The behavior of BSG biopolymers under subW pretreatment was monitored by evaluating the chemical composition of the liquid and solid streams and the chemical and structural changes caused in the solid residues by scanning electron microscope (SEM), CHNS elemental analysis and water retention value (WRV). The production of bioethanol from subW-pretreated BSG was assessed by separate hydrolysis and fermentation (SHF) and also by simultaneous saccharification and fermentation (SSF) by using the enzymatic cocktail Celluclast 1.5 L (40 FPU/gsolids) and the yeast Ethanol Red®. The higher bioethanol productivity (1.073 g∙L-1∙h-1) and concentration (32.18 g/L) were achieved by SSF with higher solids' loading (25%) and following a fed-batch strategy. These results suggest that subcritical water pretreatment is a promising technology for the valorization of BSG as a feedstock for second-generation bioethanol production.

Liquid hot water pretreatment combined with high-solids enzymatic hydrolysis and fed-batch fermentation for succinic acid sustainable processed from sugarcane bagasse

In order to sustainable process of bio-succinic acid (SA), response surface methodology (RSM) was applied to optimize liquid hot water pretreatment pretreatment of sugarcane bagasse (SCB), followed by high-solids enzymatic hydrolysis of pretreated residual that without washing, then the hydrolysates and partial pretreatment liquid were used as carbon sources for SA fermentation. Results showed that the highest sugars yield could be achieved at pretreatment conditions of temperature 186 °C, time 25 min and solid-to-liquid ratio 0.08; enzymatic digestion the pretreated residuals at 20 % (w/v) solid content via enzymes reconstruction and fed-batch strategy, the obtained sugars reached to 121 g/L; by controlling the nutrition and conditions of the fermentation process, most of the C5 and C6 sugars in the hydrolysate and pretreatment liquid were converted into SA with a conversion rate high to 280 mg/g SCB. This study can provide a novel clue for clean and efficient biorefining of chemicals.

Sustainable bioprocess combining subcritical water pretreatment followed by anaerobic digestion for the valorization of jabuticaba (Myrciaria cauliflora) agro-industrial by-product in bioenergy and biofertilizer

The management of agri-food by-products has received worldwide attention due to concerns about the environmental impacts caused by incorrect deposition. This study presented a sustainable bioprocess combining subcritical water pretreatment (SWP) followed by semi-continuous anaerobic digestion (AD) for the valorization of jabuticaba (Myrciaria cauliflora) agro-industrial by-product in bioenergy and agricultural fertilizer. The SWP was conducted at 180 °C, 15 MPa, water flow rate of 10 mL min−1, solvent to feed of 22.5 g g−1, and a kinetic time of 45 min. The AD process was operated in semi-continuous mode under mesophilic and methanogenic conditions. The results demonstrated that the hydrolysate presented glucose (5.78 g L−1), fructose (3.63 g L−1), arabinose (1.82 g L−1), and cellobiose (1.28 g L−1) as major compounds. The use of pretreated jabuticaca by-product increased the methane yield (239.04 L CH4 kg−1 TVS) in the designed bioprocess combining SWP and AD when compared to the AD without pretreatment (42.31 L CH4 kg−1 TVS). The methane produced in the bioprocess with SWP followed by AD can generate 543 kWh t−1 of electricity and 2,243.17 MJ t−1 of heat, avoiding a total of 177.54 kg CO2-eq t−1. The digestate generated after AD can be used as a biofertilizer up to a concentration of 0.3 g L−1, without toxic effects on the germination of Lactuca sativa. Finally, the sustainable bioprocess designed could be an alternative to the management of jabuticaba by-product within a circular economy framework, producing bioenergy and agricultural fertilizer that can reduce greenhouse gas emissions and environmental pollution in the food industry.

Direct consolidated bioprocessing for d-glucaric acid production from lignocellulose under subcritical water pretreatment

d-glucaric acid production from lignocellulose is a valuable research field, but meets the same challenge as other biorefinery processes that prevents it from commercialization, high production costs. The very path to tackle this is to increase the titer, rate and yield (TRY) of d-glucaric acid production and simplify the process, on which this study focused. Herein we used a novel, clean and environmentally friendly pretreatment, subcritical water pretreatment (SCWP), based on which we compared consolidated bioprocessing (CBP) by the microbial consortium composed of Trichoderma reesei C10 and Saccharomyces cerevisiae LGA-1C3S2 with separated hydrolysis and fermentation (SHF). CBP was found to be advantageous over SHF because of its comparable yield, much more simplified bioprocess and bigger space for cost reduction. Then CBP was upgraded to direct consolidated bioprocessing (dCBP) by adapting the microbial consortium in the raw liquors of SCWP containing inhibitors and toxic chemicals. As a result, more integrated biorefinery processes from corn stover (CS), wheat straw (WS), rice straw (RS) and switchgrass (SG) to d-glucaric acid under SCWP were developed and scaled up from shake flasks to 10 L fermenters, stirred and airlift. The TRYs of d-glucaric acid were improved significantly. The airlift fermenter was preferable for the dCBPs, producing the highest concentrations of d-glucaric acid, which were 10.03 g/L from subcritical water pretreated CS (SWCPCS), 9.53 g/L from SWCPWS, 8.87 g/L from SWCPRS and 10.66 g/L from SWCPSG respectively. Subsequently, the dCBPs were coupled with the downstream separation to establish a closed-circuit circulation and 30 rounds was run successfully. The highly integrated process from lignocellulose to d-glucaric acid with the smallest number of single unit operations was obtained and reported for the first time, providing an important design for biorefinery. This work is of great significance for biomanufacturing d-glucaric acid and other bio-based chemicals.

Hydrogen-Rich Water Pretreatment Alleviates the Phytotoxicity of Bispyribac-Sodium to Rice by Increasing the Activity of Antioxidant Enzymes and Enhancing Herbicide Degradation

Bispyribac-sodium (BS) is an herbicide often used to control weeds in rice fields. Hydrogen-rich water (HRW) has recently been recommended for alleviating adverse effects, but whether and how HRW alleviates the injury to rice from exposure to BS is still largely unknown. In this study, a greenhouse hydroponic experiment showed that BS alone could substantially inhibit the plant height and fresh weight of both indica and japonica rice seedlings. For indica rice, its pretreatment with HRW at 75% saturation could markedly alleviate the impact on its size but not so with either 50% or 100% HRW. For japonica rice, all the concentrations of HRW used in this study (50%, 75%, and 100% HRW) were capable of reversing the plant size reductions. Further results revealed that the HRW supplement could increase the activity of antioxidative enzymes, including that of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD), which assist in the effective removal of ROS (reactive oxygen species). Subsequent results demonstrated a weaker inhibition of the acetolactate synthase (ALS) enzyme within five days by BS in rice seedlings pretreated with HRW than those receiving the BS treatment alone, and that the HRW pretreatment can hasten the rate at which BS is degraded in rice. Taken together, these findings strongly suggest that pretreatment with HRW may offer a promising and effective strategy to improve the ability of rice to tolerate BS.

Mutual activation between ferrate and calcium sulfite for surface water pre-treatment and ultrafiltration membrane fouling control

In this work, ferrate (Fe(VI)) and calcium sulfite (CaSO3) were combined to treat surface water for improving ultrafiltration (UF) performance. During the pre-treatment process, the Fe(VI) and CaSO3 activated each other and a variety of active species (Fe(V), Fe(IV), OH, SO4−, 1O2, etc.) were generated. All of the five fluorescent components were effectively eliminated to different extents. With Fe(VI)/CaSO3 = 0.05/0.15 mM, the dissolved organic carbon and UV254 reduced by 44.33 % and 50.56 %, respectively. After UF, these values were further decreased with the removal rate of 50.27 % and 70.79 %. In the UF stage, the terminal J/J0 increased to 0.42 from 0.17, with the reversible and irreversible fouling decreased by 67.08 % and 79.45 % at most. The membrane pore blocking was significantly mitigated, as well as the foulants deposition on membrane surfaces was decreased to some extent. The complete blocking was altered to standard blocking and intermediate blocking, the volume when entering cake filtration was also delayed slightly. The extended Derjaguin-Landau-Verwey-Overbeek theory was employed to judge the interface fouling behavior, and the results indicated that the foulants became more hydrophilic, as well as the adhesion trend between foulants and membrane surface was weakened. Overall, these results provide a theoretical foundation for the practical application of the combined Fe(VI)/CaSO3-UF process in surface water purification.

Bioconversion of cellulose and hemicellulose in reed sawdust to xylo-oligosaccharides and L-lactic acid

Much of the carbohydrate-rich reed sawdust (RS) produced from the reed pulping mills is burned or buried, causing a waste of resources. The aim of this work is to effectively bio-convert cellulose and hemicellulose of RS to L-lactic acid and xylo-oligosaccharide (XOS) after liquid hot water (LHW) pretreatment. The experiments were carried out via separation hydrolysis fermentation (SHF) and simultaneous saccharification fermentation (SSF) by optimizing the culture and fermentation conditions of a probiotics compound composed of a consortium of lactic acid bacteria. In the end, functional feed additives containing 69.33 wt% L-lactic acid and 26.82 wt% XOS can easily be obtained without additional handling by SSF configuration at 40 ℃ for 82 h with the initial fermentation pH 7.0. The conversion rate of glucose to L-lactic acid reached 72.33%. The bioconversion of available portion in RS into XOS and L-lactic acid paves a new way for high-value utilization of reed residue resources.

Iron oxide-modified pervious concrete filter for lead removal from wastewater

The effects of partially adding iron-oxide-modified aggregate to OPC-based pervious concrete filter on the mechanical properties, heavy metal removal and leaching were investigated. Up to 10% of both coarse and fine aggregates were coated with iron oxide and filters (IOMA-C, coarse alone modified, IOMA-F fines alone modified and IOMA-CF) were prepared. Compressive strengths of the concrete improved while the permeability decreased by up to 13%. Simulated wastewater containing 15 ppm lead Pb (II) ions was passed through the control and IOMA-filters for 8 h under trickling water head. Iron-oxide-modified filter (IOMA-CF) showed maximum removal efficiency of 99.1% (87.3% for control). Desorption studies with 1M HNO 3 indicated that iron oxide complexed the Pb (II) ions more irreversibly, reducing the extent of their leaching. Batch studies were carried out at 1 g/L adsorbent loading (crushed control and IOMA-CF) with solutions containing 5 to 25 ppm Pb (II). Langmuir isotherm fit adsorption results on both the control and IOMA-CF systems while Temkin isotherm was the best fit for IOMA-CF, indicating the stronger, more irreversible chemisorption of Pb (II) on iron oxide. Theoretical adsorption capacities based on Langmuir isotherms for the control and IOMA-CF were 18.21 and 20.66 mg/g, respectively. Kinetics studies indicated that a pseudo second order kinetics model fit the results of all systems with a slightly slower rate of adsorption than the control system. Effects of pH and coexisting ions have been examined. These preliminary results indicate the potential of applying pervious concretes either as water filters or pretreatment units. • Pervious concrete filters with iron oxide-coated coarse and fine aggregates. • Pb(II) removal efficiencies from 93.6% to 99.1% from water. • Stronger chemisorption of Pb(II) on iron-oxide modified system — Temkin isotherm. • Pseudo-second-order kinetics, chemisorption is rate-limiting step. • Fast charge-based physisorption followed by slower chemisorption mechanism.

Pre-Treatment and Turbidity Reduction of Sea Waters Using New Composite Ceramic Microfiltration Membranes with Iron Oxide Additive

In this research, an experimental study was carried out on the pre-treatment and turbidity removal of Persian Gulf water using cross flow microfiltration by new composite ceramic membranes. Three types of tubular microfiltration composite ceramic membranes that consisted of Mullite, Mullite/SiC, and Mullite/SiC/Fe2O3 with different compositions were fabricated at relatively low temperature (1250 °C) with extrusion and sintering for this purpose. Furthermore, changes in porosity, pore size, and mechanical strength were compared in Mullite membranes and composite membranes to find the most suitable membrane for turbidity removal from seawater. According to the results, the most suitable synthetic membrane was M/SiC/Fe10 membrane with 60:30:10 ratios of mullite, silicon carbide, and iron oxide with 64.6 ± 2% porosity, average pore size of 0.54 μm, 95.4% turbidity removal, pure water permeability of 3811 L/m2.h, and higher mechanical strength (22.4 MPa) compared to other fabricated membranes. Results of Hermia’s models for fouling modeling indicated that the dominant mechanism of blocking in all membranes was standard pore blocking with the best compliance with experimental data. Therefore, results demonstrated that the addition of Fe2O3 to silicon carbide ceramic microfiltration membranes, with a specific weight percentage, improves their mechanical properties and membrane performance for pre-treatment of seawaters.