Ferric Chloride Dosage Research Articles

Reduction of organic matter and disinfection by products formation at surface water treatment plants in Egypt

ABSTRACT Although the removal of colloidal particles continues to be an important reason for using coagulation, currently a newer approach, the removal of organic matter to reduce the formation of disinfection byproducts (DBPs) such as trihalomethanes (THMs) are suspected carcinogens. Inefficient removal of total organic carbon (TOC) leads to the formation of carcinogenic THMs. This motivates the research efforts to find a way to reduce them in potable water. The first objective of this research is monitoring the water quality (raw and produced) for selected three water treatment plants within Giza Governorate to reveal the most polluted site (high TOC in the raw water and THMs in the treated water) in the study areas. The second objective of this study is enhancing coagulation to reduce TOC and THMs from surface water treating. In this study, two different coagulants aluminum sulfate (alum), and ferric chloride were tested under different conditions of pH and coagulant concentration to determine their effectiveness for removal of TOC, THMs and turbidity. Optimum values for the mentioned conditions were used to achieve the maximum reduction for TOC and THMs in Al-Ayat drinking water treatment plant (DWTP) which recorded the highest concentration of TOC and THMs. Ferric chloride as a coagulant achieved the maximum removal percentage % of TOC, THMs and turbidity as 79%, 82% and 94%, respectively, at ferric chloride dose 100 mg/L, while alum as a coagulant recorded the maximum removal percentage % of TOC, THMs and turbidity as 46%, 52% and 91%, respectively, at alum dose 100 mg/L. The results indicated that ferric chloride as a coagulant has the highest efficiency reduction of TOC, THMs and turbidity if compared to alum with the same dose added.

Arsenic Treatment Using Electrolytic Ferrous Reagent to Replace Bulk Ferric Chloride

Key TakeawaysAs federal maximum contaminant level (MCL) recommendations for arsenic in drinking water are being reviewed, US utilities are preparing for more stringent regulations.If faced with reducing its treated water's arsenic concentration to 5 μg/L, the City of Alamosa, Colo., would need to increase its ferric chloride dose—raising supply, cost, and operational concerns.To avoid these issues, the city explored a new technology that generates a ferrous reagent via an in situ electrolytic process to replace bulk ferric chloride.The electrolytic ferrous reagent removed arsenic to below 5 μg/L, reduced permeate manganese levels, and improved effluent quality with a far lower coagulant dose.

Optimization of the Coagulation-flocculation Process Using Ferric Chloride and Phosphate for the Reduction of Contaminants in the Slaughterhouses Wastewater

In this work, the coagulation-flocculation process was optimized using ferric chloride and phosphate for the reduction of pollutants in the wastewater from the Conchucos S.A., Lima. Parameters were measured in percentage reduction of chemical oxygen demand (COD), turbidity (NTU) and total phosphorus (PT mg/L), adding ferric chloride as coagulant and potassium dihydrogen phosphate as flocculant. The effects of four independent variables were investigated: ferric chloride dose (500-700 ppm), phosphate dose (700-900 mg/L), fast agitation speed (250-320 rpm) and slow agitation speed (90-100 rpm). The experimental data were optimized by the response surface method using a central composite design. The results show that the statistical models obtained F-values of 3.33, 4.27 and 4.16 for the percent reduction of COD, turbidity and total phosphorus, respectively. Furthermore, the statistical models developed to predict the responses were confirmed by significant probability values (p<0.05). On the fit of the models, an R2 of 0.61, 0.66 and 0.67 are shown for COD, turbidity and total phosphorus percentage, respectively. The optimum conditions were found experimentally at 700 ppm of ferric chloride dose, 900 ppm of phosphate, 320 rpm fast speed and 100 rpm for a reduction of 75.46% of COD, 83.47% of turbidity and 44.08% of total phosphorus presenting a desirability of 0.7.

Competitive Removal of Antimony and Humic Acid by Ferric Chloride: Optimization of Coagulation Process Using Response Surface Methodology

The co-contamination of aquatic systems with antimony (Sb) and humic acid (HA) is a global concern due to their potential risks to human health and environment. In this research, three-level-three-variable Box–Behnken design (BBD) was investigated for simultaneous Sb(III) and total organic carbon (TOC) removal responses from groundwater by use of ferric chloride (FC) as a coagulant. This study focuses on three operating variables, including initial Sb(III) concentration (100, 550, and 1000 μg/L), HA concentration (2, 6, and 10 mgC/L) and FC dosages (20, 60, and 100 mg/L). The proposed quadratic model presented good correlation with experimental values having R2 and adjusted R2 values of response variables (Sb(III): 0.9981 and 0.9956) and (TOC: 0.9935 and 0.9851), respectively. The most pronounced influence of FC dosage was observed in the removal responses of TOC and Sb(III). Interestingly, the model revealed that a high level of FC dosage had the same TOC removal potential regardless of increasing HA concentration. The statistical model for both Sb(III) and TOC responses was used to optimize the experimental conditions. Moreover, the experimental results were successfully validated with predicted values having high accuracy. The sludge volume produced for studied variables followed the decreasing order as FC dosage > HA concentration > Sb(III) concentration. Under optimum conditions, 0.45 mL/L sludge volume was produced in the treatment of ground water in Nawabshah. In general, the results of the current study may provide some insights into the predictability of simultaneous removal performance of Sb species and organic substances from groundwater.

The Optimization of Operational Variables of Electrochemical Water Disinfection Using Response Surface Methodology

The electrochemical treatment of canal water was investigated in a batch-wise system in the presence of stainless steel 316-grade electrodes. Three effective process parameters, including current density, reaction time, and electrode spacing, were evaluated in the range of 0.25–2.5 mA/cm2, 1–10 min, and 0.5–2.5 cm, respectively. Operational variables of electrochemical disinfection are optimized in response surface methodology (RSM) using Box–Behnken design. Before electrochemical disinfection, a pretreatment process of coagulants mixing for turbidity removal was conducted. Results revealed that a 10 ppm dosage of Ferric chloride (FeCl3.6H2O) and alum (Al2(SO4)3·16H2O) at neutral pH is appropriate. Furthermore, the RSM analysis shows that interelectrode spacing is the most prominent factor affecting the disinfection performance, and increasing electrode spacing inversely affects the disinfection efficiency. Results revealed that 1.52 mA/cm2 current density, 6.35 min reaction time, and 1.13 cm of electrode spacing are the optimum conditions, resulting in a statistically 98.08% disinfection of the total coliform. The energy required for electrochemically disinfection of water at optimum conditions was 0.256 kWh/m3.

Optimization of a compact on-site stormwater runoff treatment system: Process performance and reactor design

Stormwater runoff has become a major anthropogenic urban pollution source that threatens water quality. In this study, coagulation-sedimentation, and ammonium ion exchange and regeneration (AIR) modules were coupled as a CAIR system to efficiently treat stormwater runoff. In the coagulation module, 99.3%, 91.7%, and 97.0% of turbidity, total phosphorus, and chemical oxygen demand could be removed at an optimized poly-aluminum ferric chloride dosage of 30 mg/L, and the continuous experiment confirmed that the full load mode was more suitable for its rapid start-up. In the AIR module, dynamic ammonium removal indicated that the breakthrough time decreased with the rising initial concentration and superficial velocity. The Modified Dose Response (MDR) model described the ammonium exchange behavior better than the Thomas and the Bohart-Adams models. Then, a design flow of the ion exchange reactor was constructed by correlating constants in the MDR model with engineering parameters, and the ion exchange reactor was designed for continuous operation of the CAIR system. The average concentrations of chemical oxygen demand, total phosphorus, ammonium nitrogen, and total nitrogen in the effluent of the CAIR system were 7.22 ± 2.26, 0.17 ± 0.05, 1.49 ± 0.01, and 1.62 ± 0.02 mg/L, respectively. The almost unchanged exchange capacity and physicochemical properties after the multicycle operation confirmed the durability of zeolite for ion exchange. Techno-economic analysis suggested that the CAIR system is practically promising for stormwater management with efficient pollutants removal, small footprint, and acceptable operating cost.

Combination of Coagulation and VUV+H2O2 for the Treatment of Color and Organic Matter in Treated Effluent Wastewater from a Sugar Factory

The removal of color and organic matter in treated effluent wastewater from a sugar factory by coagulation, combined with advanced oxidation processes (AOPs), including UV, UV+ hydrogen peroxide (UV+H2O2), vacuum UV (VUV), and VUV+H2O2, was investigated in this study. The effect of pH and a dose of coagulants (aluminum sulfate (alum), polyaluminium chloride (PACl), ferric chloride (FeCl3), and ferric sulfate (Fe2(SO4)3)), as a pretreatment step prior to AOPs, was analyzed. The optimum pH and coagulant dose for coagulation was pH 6 and 600 mg/L, respectively. The iron-based coagulants generally provided the better removal efficiency than the aluminium-based coagulants. Among four coagulants, FeCl3 was chosen for use in the pretreatment step since it provided the best performance for dissolved organic carbon (DOC) removal, UV transmission improvement, and cost-effectiveness. The removal efficiency and degradation rate of color, UV absorbance at 254 nm (UV254), and DOC increased along with the H2O2 dosage. The reduction of UV254 indicated a less aromatic portion of DOC after AOPs. The ratio of DOC:H2O2 at 1:3 yielded the highest DOC removal of 70 ± 0.42 and 73 ± 0.19% in 60 min by UV+H2O2 and VUV+H2O2, respectively. For energy efficiency, VUV+H2O2 (DOC:H2O2 =1:3) provided the lowest electrical energy per order (EEO) (26 kWh/m3). After coagulation, DOC combined with VUV+H2O2 was reduced to the appropriate level for reuse (4 mg/L). The findings from this research demonstrate the promise of coagulation coupled with the VUV+H2O2 process as a technology for water reuse application in the sugar industry.

Mechanistic study on the ferric chloride-based rapid cultivation and enhancement of aerobic granular sludge

ABSTRACT Aerobic granular sludge (AGS) can achieve simultaneous carbon, nitrogen and phosphorus removal owing to its three-dimensional oxygen gradient structure. However, long start-up period and poor operational stability restrict its application and promotion. A novel rapid granulation strategy, viz., the short-term (7 days) addition of ferric chloride at the commissioning stage, was developed and verified in this study. The granulation period was shortened by 9 days, and the formed granules were compact and dense with an Fe3+ concentration of 250 mg L−1. The addition of flocculant not only maintained a high sludge concentration during the initial stages of granulation (5.3 g L−1), but also stimulated the secretion of TB-EPS and increased protein and polysaccharide contents, thereby expediting granule formation. Additionally, ferric chloride induced a diverse microbial community in granules, resulting in the emergence of new genera, such as Thaurea, Brevundimonas and Kinneretia, which improved pollutant removal performance and flocculent aggregation. The removal efficiencies of COD, PO4 3--P, and NH4 +-N stabilized at 94.2, 62.4, and 71.3%, respectively. Therefore, it has been demonstrated that short-term ferric chloride dosing has a synergistic effect on aerobic granulation.

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

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

Influence of external electric field on polymerization of Fe (III) flocculant in water: A reactive molecular dynamics and experiment study

In the present study, a novel method of electrochemically enhancing hydrolysis of Fe (III) was proposed. The influence of an external electric field (EEF) on initial polymerization of Fe(III) was investigated by using reactive MD simulation method. It is examined in term of the structural property (radial distribution function), bond order, electrostatic energy, polymerization products, and kinetic characteristic (self-diffusion coefficient) in the hydrolysis system. Then an experimental study was carried out to verify the MD simulation conclusions. The results show that EEF can shorten the distance between Fe3+ ions, enhance the bonding strength between Fe3+ ions, enhance the activity of particles, thus promote the formation of dimer [Fe2(OH)2(H2O)8]4+, and further produce particles with larger size and surface area, which is beneficial to enhance the ability of particles to adsorb impurities. Then the experimental results of particle size distribution of FeCl3 flocculating particles and the Zeta potential of the FeCl3 solution under different EEF meet well with the MD simulation conclusions. The method of electrochemically enhancing hydrolysis proposed in this paper is expected to effectively improve the flocculation performance of ferric chloride, and then reduce the dosage of ferric chloride in practical application.

Removal of Arsenic Oxyanions from Water by Ferric Chloride-Optimization of Process Conditions and Implications for Improving Coagulation Performance.

The chronic ingestion of arsenic (As) contaminated water has raised significant health concerns worldwide. Iron-based coagulants have been widely used to remove As oxyanions from drinking water sources. In addition, the system’s ability to lower As within the maximum acceptable contamination level (MCL) is critical for protecting human health from its detrimental effects. Accordingly, the current study comprehensively investigates the performance of As removal under various influencing factors including pH, contact time, temperature, As (III, V) concentration, ferric chloride (FC) dose, and interfering ions. The optimum pH for As (V) removal with FC was found to be pH 6–7, and it gradually decreased as the pH increased. In contrast, As (III) removal increased with an increase in pH with an optimum pH range of 7–10. The adsorption of As on precipitated iron hydroxide (FHO) was better fitted with pseudo-second order and modified Langmuir–Freundlich models. The antagonistic effect of temperature on As removal with FC was observed, with optimum temperature of 15–25 °C. After critically evaluating the optimum operating conditions, the uptake indices of both As species were developed to select appropriate an FC dose for achieving the MCL level. The results show that the relationship between residual concentration, FC dose, and adsorption affinity of the system was well represented by uptake indices. The higher FC dose was required for suspensions containing greater concentration of As species to achieve MCL level. The As (V) species with a greater adsorption affinity towards FHO require a relatively smaller FC dose than As (III) ions. Moreover, the significant influence of interfering species on As removal was observed in simulated natural water. The author hopes that this study may help researchers and the drinking water industry to develop uptake indices of other targeted pollutants in achieving MCL level during water treatment operations in order to ensure public health safety.

Understanding and mitigating effects of brine discharge to wastewater on primary sedimentation

AbstractAs the implementation of full advanced treatment with reverse osmosis (RO) grows in response to water scarcity, the effects of RO brine disposal to sewersheds on wastewater treatment will become an increasingly important consideration. Unfortunately, there is little existing literature on the actual effects of brine augmentation on wastewater flocculation and settling. In this study, RO brine from a wastewater reuse system was blended into raw wastewater. Jar tests of chemically enhanced primary treatment (CEPT) were conducted with varying brine blends and ferric chloride coagulant doses. Brine augmentation, at volumetric fractions ranging from 2.7% to 54% of the primary influent, was observed to affect CEPT performance, as removal of turbidity and total suspended solids (TSS) decreased in response to increasing brine share. Control jars with 0% brine generally had greater than 80%–90% TSS removal at the baseline coagulant dose of 12.5 mg/L, and this decreased to around 70% at 27% brine and less than 70% at 54% brine. This effect was observed to be roughly proportional to the level of brine addition, and it appears to be driven by changes to the properties of the fluid and primary particles as a result of brine addition. Adding brine both increases the density and viscosity of the fluid through higher total dissolved solids and decreases the density of the primary particles that make up the floc by contributing dissolved organics rejected by RO. CEPT performance was restored to its current baseline of around 80%–90% removal of TSS and turbidity by increasing ferric chloride dose (and thus floc density), with 17 mg/L required at 2.5% brine share and 30 mg/L required at 15% brine share. Overall, there was a roughly linear relationship between influent brine proportion and additional coagulant required to bring CEPT performance back up to brine‐free levels. The impact observed in this study suggests a topic for future research with other sources of brine and other coagulants.Article Impact StatementBy investigating primary settling affected by RO brine, this work addresses a topic of current interest that has not been widely studied.

Treatment of a landfill leachate from Casablanca city by a coagulation-flocculation and adsorption process using a palm bark powder (PBP)

The study aims to evaluate the efficiency of a combined landfill leachate treatment (coagulation with ferric chloride coupled with adsorption onto palm bark powder (PBP)) enhance a low cost bioadsorbent. The efficiency of this treatment, was assessed in terms of chemical oxygen demand (COD), color and turbidity removal. This bioadsorbent was subjected to physico-chemical and morphological characterization by different methods (Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), N2 adsorption-desorption isotherms, pH at zero charge point (pHPZC) and Boehm titration method).The coagulation process reduced the turbidity by 90%, the COD by 50%, the color by 80% and the biological oxygen demand (BOD5) by 99% for the optimum dose of ferric chloride of 12 g Fe3+. L−1. Thereafter, the sequential treatment of a landfill leachate based on coagulation as a pre-treatment process and then adsorption onto PBP improves the removal of turbidity, COD and color to 99%, 59% and 90%, respectively.These results demonstrate that combined coagulation-flocculation and adsorption processes could be a useful option for the treatment of solid-waste landfill leachate.

Optimization of Antimony Removal by Coagulation-Flocculation-Sedimentation Process Using Response Surface Methodology

Coprecipitation-adsorption plays a significant role during coagulation-flocculation-sedimentation (C/F/S) of antimony (Sb) in water. This work uses a Box–Behnken statistical experiment design (BBD) and response surface methodology (RSM) to investigate the effects of major operating variables such as initial Sb(III, V) concentration (100–1000 µg/L), ferric chloride (FC) dose (5–50 mg/L), and pH (4–10) on redox Sb species. Experimental data of Sb(III, V) removal were used to determine response function coefficients. The model response value (Sb removal) showed good agreement with the experimental results. FC showed promising coagulation behavior of both Sb species under optimum pH (6.5–7.5) due to its high affinity towards Sb species and low residual Fe concentration. However, a high dose of 50 mg/L of FC is required for the maximum (88–93%) removal of Sb(V), but also for the highest (92–98%) removal of low initial concentrations of Sb(III). Furthermore, BBD and RSM were found to be reliable and feasible for determining the optimum conditions for Sb removal from environmental water samples by a C/F/S process. This work may contribute to a better understanding and prediction of the C/F/S behavior of Sb(III, V) species in aqueous environments, to reduce potential risks to humans.

Preparation and characterization of cellulosic conductive paper

Silver nanowires were successfully prepared by polyol method using silver nitrate as silver source, ethylene glycol as solvent and reducing agent, and ferric chloride as nucleating agent and polyvinylpyrrolidone (PVP) as structure directing agent and protective agent. The obtained silver nanowires were mixed with Kraft pulp fibers and bacterial cellulose to prepare conductive paper via simple filtration process. The results indicated that the size of silver nanowires can be regulated by the dosage of ferric chloride used. At optimal dosage of FeCl3, the prepared silver nanowires can reach 20 μm length, 100 nm width, and 200 of width/diameter ratio. The adding of bacterial cellulose in preparing the conductive paper greatly enhanced the retention ratio of silver nanowires as well as the stress and strain of the conductive paper. The stress and strain of the paper with bacterial cellulose were increased by 60% and 7%, respectively, compared with that of the paper without bacterial cellulose. The maximum retention ratio and the highest recovery ratio of silver nanowires in conductive paper reached 94% and 75%, respectively. The resistance of as-prepared conductive paper was only 0.9 Ω. In conductive paper, the silver nanowires attached to the paper-based materials with cellulose fibers as the substrate, which achieved the electrical conductivity of paper-based materials. This conductive paper can be applied as antistatic, antibacterial packaging and conductive material.

Study on optimal conditions of poly ferric chloride (PFC) dosage treating tannery wastewater

Tannery wastewater was considered as a heavily industrial wastewater with very high amount of wastewater discharged everyday but not well-treating. The tanning wastewater from producing process contains various high strength toxic chemicals which could do the inhibition for biological treatment process leading to low quality effluent. It is required to perform the pre-treatment process by physical–chemical treatment including coagulation and flocculation in order to reduce the content of toxic chemicals before biological treatment. This study focused on investigate on the performance of Poly Ferric Chloride (PFC) as a flocculant for flocculation process in tannery wastewater treatment due to its advantages which could apply in a wide range of industries to help remove materials suspended in water. The application of PFC was conducted in batch test to find the optimum conditions including pH, PFC dose, and rotation speed in term of treating tannery wastewater performance. In addition, a common flocculant polyaluminium chloride (PAC) was chosen to compare with PFC in term of treatment efficiency and cost effective. As the result, with 0.4 ml/l PFC, pH – 10.4 with 100 rpm spins, it reaches its efficient treatment COD process to 93,3%; NH4+ 90,4% and SO42- 79,2% with could easily promote a potential alternative flocculant with excellent performance but lower cost.

Low-cost biomass for the treatment of landfill leachate from Fez City: application of a combined coagulation–adsorption process

In this work, the efficiency of a novel treatment of solid-waste landfill leachate based on coagulation and then adsorption onto a natural bioadsorbent was examined. The reduction in the chemical oxygen demand (COD), biological oxygen demand (BOD5), turbidity, and color of the leachate from the urban sanitary landfill in Fez City (Morocco) following treatment was evaluated. Ferric chloride was used as the coagulant in the coagulation–flocculation pretreatment of the leachate, and Cupressus sempervirens cones were employed to adsorb the contaminants in the coagulated leachate. The optimum dose of ferric chloride was found to be 20 g per liter. The resulting coagulation process reduced the COD by 69%, the BOD5 by 60%, and the color of the leachate by 88%. Following the adsorption of the pretreated landfill leachate on Cupressus sempervirens cones, the COD, BOD5, and color of the leachate were found to be 86%, 96%, and 93% lower than their original values, respectively. The adsorption capacity of the treatment qe was calculated as 385 $${\text{mg}}_{{{\text{O}}_{ 2} }} \;{\text{g}}^{ - 1}$$ for 1 g of Cupressus sempervirens cones per liter under optimal adsorption conditions (including pH 7, 25 °C, and 8 h of contact time). A study of the adsorption kinetics for the COD revealed that a pseudo-second-order model provided the best fit to the experimental kinetic data, and the equilibrium data were well described by the Langmuir isotherm model. These results of the study indicate that the novel combined coagulation–adsorption treatment of landfill leachate is an inexpensive alternative to current landfill leachate treatments, and is suitable for application to industrial-scale sanitary landfills.

Removal and recovery of selenium species from wastewater: Adsorption kinetics and co-precipitation mechanisms

This study investigates the effectiveness of four adsorbent candidates, including nano-zerovalent iron (nZVI), magnetite (Fe3O4), ferric chloride (FeCl3) and granular activated carbon (GAC) to remove inorganic and organic selenium species from contaminated water. The efficacy of the modified co-precipitation method using a combination of ferrous and ferric chloride was also investigated. Among the adsorbents tested, ferric oxyhydroxide flocs formed by the precipitation of ferric chloride was found to be most efficient as more than 95 % of Se (VI) was removed using ferric chloride dose of 1 g/L. The optimum pH for removal of Se (VI) irrespective of the adsorbent was found to be in the range of 4.0–5.5. Comparatively, Se (IV) was removed faster and required lesser adsorbent doses for all adsorbents tested. The experimental data fitted well with Langmuir model compared to Freundlich model indicating the monolayer adsorption. While metallic adsorbents were found to show better performance for removal of inorganic selenium species, GAC showed a higher affinity towards the removal of selenomethionine, an organo-selenium compound. About 50 % of selenomethionine was removed within a contact time of one hour for GAC dose of 0.5 g/L, while about 9% and 7% removal was observed for the same doses of Fe3O4 and nZVI powders respectively. In contrast to electrostatic attraction, which is considered to be the main drive for adsorption of inorganic selenium, van der Waals attraction is supposed to drive adsorption of selenomethionine.

Soil Stabilization by using fly ash and Ferric Chloride

The soil is stabilized with fly ash and ferric chloride mixtures in this research paper. The Serviceability of the pavement is very tractable to the soil sub-grade properties. For that reason, a weaker sub-grade can be improved by using the most effective stabilization method. Based on the literature review, stabilization with fly ash activated sub grade has been found to be an effective option for improvement of soil properties. Stabilization of the soil is mostly done in soft soils such as organic soil, clayey peat, silt. Some of the wastes used are fly ash, marble dust, foundry sand, rice ash and so on. These materials not only provide an alternative to the use of conventional materials but also help control environmental pollution. In many places, the waste is dumped into the open air, which can be very problematic for the people in the area and the workers working in these areas. Using these waste materials not only reduces pollution but also reduces human credibility on natural resources, leading to a more sustainable process of construction. It was found from the literature that the optimum dose of fly ash and ferric chloride revealed essential enhancement in strength and durability characteristics and declination in the swelling and plasticity properties of the soil. Based on that result, it is suggested that a mixture of fly ash and ferric chloride should be take into consideration a workable option for the stabilization of broad subgrades.

Effect of ferric chloride on phosphorus immobilization and speciation in Dianchi Lake sediments.

Immobilization of phosphorus in lake sediments and control of internal-loading phosphorus release have become crucial aspects of eutrophication lake management. In this study, the immobilization efficiency of phosphorus by ferric chloride in Dianchi Lake sediments was investigated. In addition, effects of the dosage of ferric chloride and contact time on the release of phosphorus from sediments were investigated. Laboratory experiments revealed that ferric chloride can effectively inhibit the release of phosphorus from sediments. At a ferric chloride dosage of 10mg/g, the total phosphorus concentration of the overlying water was reduced by ~87%. With the increase in the contact time, the amount of phosphorus immobilized by ferric chloride increased. To further evaluate the feasibility of ferric chloride for immobilising phosphorus in sediments, an amplification experiment with a water volume of 50L was carried out. By the addition of 6mg/g of ferric chloride, the total phosphorus concentration of the overlying water was still less than 0.01mg/L after 100 days. At the same time, the phosphorus species in the sediment after treatment with ferric chloride were analyzed. Results revealed that ferric chloride mainly converts unstable exchangeable phosphorus (Ex-P), ferric phosphate (Fe-P) and organic phosphorus (Or-P) into more stable occluded phosphate (O-P), reducing the possible release of phosphorus from sediments. Practical applications of ferric chloride to control the release of phosphorus from Dianchi Lake sediments were discussed.