Caffeine Adsorption onto Bentonite Clay in Suspension and Immobilized

Abstract This study describes the use of bentonite in suspension for the caffeine adsorption (pollutant of emerging concern) by taking different conditions of the pH, adsorbent mass, adsorbent calcination temperature and interferents into account. The results were compared with those obtained using bentonite immobilized in alginate beads. The acid medium has a greater efficiency for the caffeine adsorption and the adsorbent calcination temperature exerts, due to structural changes. Caffeine removal higher than 90% was obtained at optimized conditions. The Langmuir model indicated a better fit of the data and the adsorption capacity of caffeine onto bentonite. The bentonite immobilized led to a slower adsorption process in relation to the suspended.

Determination of five pesticides in fishpond by SPE-GC/MS / 法医学杂志

OBJECTIVE@#To establish the solid phase extraction (SPE) with GC/MS technology for fish poisoning cases to determine five pesticides in fishpond.@*METHODS@#By three solid phase extraction column including Oasis HLB cartridge, Bond Elut C18 and SampliQ C18, the recovery rate was compared to extract and purify five pesticides in fishpond. The effects of different kinds and dosages of eluents on extract rate were also reviewed.@*RESULTS@#Using Bond Elut C18 as solid phase extraction column and 3 mL benzene as eluent, the linear range of mass concentration of five pesticides in fishpond was 1-50 μg/mL, and the correlation coefficient was 0.996 2-0.999 6. The limit of detection was 3.4-26 μg/L and the recovery was 61.49%-102.48%. The relative standard deviations was less than or equal to 3.01%. CONCLU-SION: With high sensitivity, good accuracy and precision, SPE-GC/MS has simple and quick operation and less solvent. It can be applied to determination of five pesticides in fishpond.

[Efficiency of Pistaciaatlantica seed extract as natural coagulant in the removal of Reactive Red 198 dye from aqueous solution]

Textile dyes and other dyes used in various industries are among the largest organic compounds which can be a major hazard to the health and environment. Therefore treatment of wastewater before discharging it into the environment is necessary. In the present study we investigated the efficiency of Pistacia atlantica seed extract in a batch system for removal of Reactive Red-198 dye from aqueous solutions. This is a basic- applications study conducted in laboratory. The effects of independent variables such as coagulant dose [0.1-1 ml L-1], initial dye concentration [50, 100, 150 and 200 mg/l] and pH [2-12] were investigated. To measure the residual concentration of dye we used a spectrophotometer at the wavelength of 520 nm. Excel software was used for data analysis. The optimum pH for Reactive Red-198 removal by coagulation using Pistacia atlantica seed extract was 12, with a coagulant dose of 0.5 ml/L. The highest removal rates were 83.12, 84.20, 87.36 and 88.49% at initial dye concentrations of 50, 100, 150 and 200 mg/L respectively, which could be result of precipitation, co-precipitation and adsorption mechanisms. According to the results of this study, Pistacia atlantica seed extract was an inexpensive coagulant, and also quite effective in the removal of Reactive Red-198 dye from aqueous environments

Synthesis of magnetite nanoparticles and evaluation of its efficiency for arsenic removal from simulated industrial waste water

In this study the efficiency of magnetic nanoparticles for removal of trivalent arsenic from synthetic industrial wastewater was evaluated. The nanoparticles was prepared by sol-gel method and characterized by X-ray methods including XRD, XRF, and SEM, and vibrating sample magnetometer [VSM]. The results showed that synthesized nanoparticles were in the size range of 40-300 nm, purity of about 90%, and magnetization of nanoparticles was 36.5emu/g. In initial conditions including: pH=7, As[III] concentration of 10 mg/L, nanomagnetite concentration of Ig/L, shaking speed of 250 rpm and 20 minute retention time, 82% of As [III] was removed. Competition from common coexisting ions such as Na[+], Ni[2+], Cu[2+], SO[4][2-], and Cl[-] was ignorable but for NO[3-] was significant. The adsorption data of magnetite nanoparticles fit well with Freundlich isotherm equations. The adsorption capacity of the Fe[3]O[4] for As [III] at pH=7 was obtained as 23.8 mg/g. It was concluded that magnetite nanoparticles have considerable potential in removal of As [III] from synthetic industrial wastewaters

DI-[2-ethylhexyl] phthalate oxidative degradation by fenton process in synthetic and real petrochemical wastewater

Di-[2-Ethylhexyl] phthalate [DEHP] belongs to the class of phthalate esters and is used as an additive in many products including plastics, paints and inks or as a solvent in industrial formulations. The degradation of DEHP in aqueous solution using oxidative Fenton reaction [H[2]O[2]/Fe[2+] was carried out in this study. It was found that H[2]O[2] concentration, Fe[2+] concentration, and pH were the three main factors that could significantly influence the degradation rates of DEHP. The highest degradation percentage [85.6%] of DEHP was observed within 60 min at pH 3 in H[2]O[2]/Fe[2+] system. The results of our study suggested that the concentration with 90 mg/L H[2]O[2] 5 mg/L Fe[2+], and 20 mg/L DEHP in the solution at pH 3 were the optimal conditions. The optimized reaction parameters were preceded for treatment of real wastewater obtained from a petrochemical plant

Thioglycolic acid esterified into rice straw for removing lead from aqueous solution

Thiol rice straw [TRS] was prepared by esterifying thioglycolic acid onto rice straw in the medium of acetic anhydride and acetic acid with sulfuric acid as catalyst. The sorption of lead [Pb] on TRS from aqueous solution was subsequently investigated. The batch experiments showed that Pb removal was dependent on initial pH, sorbent dose, Pb concentration, contact time, and temperature. The maximum value of Pb removal appeared at pH 5. For 100 mg/L of Pb solution, a removal ratio of greater than 98% could be achieved with 2.0 g/L or more of TRS. The isothermal data of Pb sorption conformed well to the Langmuir model, and the maximum sorption capacity [Q[m]] of TRS for Pb was 104.17 mg/g. The equilibrium of Pb removal was reached within 120 min. The Pb removal process could be described by the pseudo-first-order kinetic model. The thermodynamic study indicated that the Pb removal process was spontaneous and endothermic

Optimization of operational parameters for decolorization and degradation of c l reactive blue 29 by ozone

Because conventional wastewater treatment of effluent containing anthraquinone dye causes notable environmental problems, it is important to find effective alternative methods for dye removal. This study evaluated the efficacy of ozonation for dye removal and Chemical Oxygen Demand reduction and identified optimal operational conditions for parameters such as pH, contact time and concentration of C.I. Reactive Blue 29 dye in a semi-batch reactor. Values of pH between 3 and 11 and contact times between 15 and 120 minutes were investigated. Dye concentrations were based on the American Dye Manufacture Institute standards and ranged from 1000 to 5000. Although results showed that Chemical Oxygen Demand removal by ozone alone was not very efficient [58%], ozonation proved to be an efficient method for decolorizing Reactive Blue 29 [96%]. pH was found to significantly influence the effectiveness of Chemical Oxygen Demand removal, and optimal pH conditions [95% confidence interval] were between 9 and 11. For decolorization, pH adjustment was not necessary. Degradation and decolorization of dye were found to be strongly influenced by the contact time, optimal conditions [95% confidence interval] for degradation and decolorization were 60 and 30 minutes, respectively. The optimal dye concentration was 1000 American Dye Manufacture Institute

Removal of malathion insecticide from water by employing acoustical wave technology

Organophosphorus pesticides are one of the most prevalent usages for pest control in the country. Such pesticides enter into water sources by different routes. Since drinking of contaminated water at the higher doses than the standard level, may causes undesirable effects to human health and ecosystem. The object of this research was to investigate the effect of various parameters including time, power and concentration on sonodecomposition of malathion insecticide in the water. The sonochemical degradation of malathion was investigated using acoustic wave technology [AWT]. AWT with 130 kHz was used to study the decomposition of insecticide solution. Samples were analyzed using HPLC at different intervals times. Effectiveness of AWT at different times [20, 40, 60, 80, 100, and 120 minutes], concentrations of malathion at 2, 4 and 8 mg/L as well as powers of device [300W, 400W, 500W] are compared. These findings showed that the degradation of the malathion insecticide at lower concentrations was greater in comparison to higher concentrations. Also, there was positive correlation between power increasing and the ability to malathion degradation. The sonodegradation of malathion at different concentrations and powers was successfully achieved. It has been shown that acoustical wave technology can be used to reduce the concentration of dissolved insecticide using high frequency

Removal of Trichloroethylene from water by adsorption on to multiwall carbon nanotubes

Groundwater recourses may be contaminated with trichloroethylene [TCE] which is used in electronic, electric, dry cleaning and other similar industries and often treated by air stripping, which TCE in its vapor form is stripped from groundwater by air and is emitted into the atmosphere without any additional treatments. Carbon nanotubes are expected to play an important role in sensing, pollution treatment and separation techniques. In this study adsorption of trichloroethylene on multiwall carbon nanotubes has been investigated. The effect of contact time, pH, initial concentration of trichloroethylene and temperature on its adsorption were investigated. Adsorption isotherms and related constants were also determined. Results showed that contact times to reach equilibrium changed from 30 min [for 150 microg/L initial concentration] to 10 min [for 600 microg/L concentrations] at 25 [degree sign]C; the equilibrium times in 40[degree sign] C were 40 min and 15 min, respectively. Multi-wall carbon nanotubes showed to act as a good adsorbent for TCE in a wide range of pH=[3-9]. For pH>9, adsorption decreased due to ionization of oxygen-containing groups. Adsorption test results revealed that TCE adsorption on the studied adsorbents could be better described by Freundlich isotherm

Effects of biosorption parameter: kinetics, isotherm and thermodynamics for Ni(II) biosorption from aqueous solution by Circinella sp

Circinella sp. was employed as a biosorbent for removal of Ni(II) from aqueous solution. The biosorption kinetics and isotherms were investigated. The effect of several parameters, such as biosorbent dosage, contact time, initial concentration, pH and temperature, on biosorption process was evaluated. The kinetic studies indicated that the biosorption followed pseudo-second order kinetic model. Biosorption behaviour of Ni(II) on Circinella sp. was expressed by both Langmuir and Freundlich isotherms. The equilibrium data fit better to the Langmuir model compared to the Freundlich model in concentration range studied (1.0-3.0 mM). The thermodynamic parameters (AG°, AH° and AS°) were also determined, and it was found that the Ni(II) biosorption by Circinella sp. was spontaneous and endothermic in nature.

[Survey of arsenic removal from water by coagulation and dissolved air floatation method]

Arsenic is one of the most toxic and dangerous elements in drinking water that with increase in its application in agriculture, development of applications in agriculture, livestock, medicine, industry and other cases its entry to water resources and environment is much easier. Arsenic is a poisonous, cumulative substance and inhibitor of SH group enzymes and various studies revealed a significant correlation between high concentrations of arsenic in drinking water and liver cancer, nasal cavity cancer, lungs, skin, bladder and kidney cancer in men and women and prostate and liver in men. The aim of this was survey of arsenic removed from water using dissolved air floatation mechanism. At present study in first step for determination best conditions of arsenic removal by dissolved air floatation method, optimum amount of coagulants determined and then synthetic solution of arsenic [50, 100 and 200 micro g/L] prepared using sodium arsenate. In third step arsenic removal efficiency under various variables such as arsenic concentration, flocculation and floatation time and saturation pressure were analyzed. Finally residual arsenic concentration was determined by the silver diethyl dithiocarbamate method. Effect of optimum condition on arsenic removal efficiency at various initial concentration 50, 100 and 200 microg/Lshowed that the best coagulant for removal of arsenic is polyaluminumchloride. Also maximum efficiency [99.4%] was obtained in initial concentration equal 200 microg/L. It can be concluded that dissolved air floatation method with poly aluminum chloride as coagulant have high efficiency for arsenic removal even at high concentrations and therefore this method can be used for removal of arsenic from water as a suitable and safe option

[Removal of methylene blue dye from synthetic wastewater with bone char]

Dyes are organic materials with complex structures, toxic, carcinogenic, teratogenic, nonbiodegredable properties and the most important pollutants of textile industrial wastewaters. The goal of this study was to survey the feasibility application of bone char [BC] as a sorbent for the removal of methylene blue [MB] from synthetic wastewater. The sub goals of the research were to determine the adsorption isotherm, effects of primary concentration of dye, adsorbent dose, contact time, and pH for the adsorption of MB with BC. BC was prepared under laboratory conditions by using of electrical furnace at 400°C for 2h. The prepared BC was crushed and pulverized by standard ASTM sieves with range of 10-16 mesh [1.18-2 mm]. The chemical composition and solid structure of BC was analyzed using X-ray diffraction [XRD] and scanning electronic microscopy [SEM]. Measurement of the surface area was carried out by N2 gas via BET isotherm and Belsorb software. The concentration of dye was measured by photometric method [663nm]. Predominant composition of BC is calcium hydroxyl apatite [Ca5 [PO4]3OH with 14m2/g surface area. The results of this study showed that increasing of primary concentration of dye, adsorbent dose and pH [5 to12] would lead to increasing of adsorption/removal of MB dye. Equilibration of dye adsorption was reached at lapse of 2h and optimum pH for adsorption of MB with BC found in the rage of 8.5-12. Adsorption of MB with BC complies with freundlich isotherm [R2: 0.99]. Conclusion: Bone char is a cheap component that can be used as an adsorbent in water and wastewater treatment. Based on optimum pH of 8.5-12 found for the removal of MB and the fact that many of textile industrial wastewaters have an alkaline pH, this adsorbent can be used for the removal of dyes from these wastewaters

Chromium (VI) tolerance in two halotolerant strains of Nostoc.

The present study reports on chromium (VI) tolerance of two cyanobacterial strains Nostoc linckia and Nostoc spongiaeforme isolated from salt affected soils using uni-algal and bi-algal systems. Besides distinct halophilism, the two strains exhibited remarkable tolerance to chromium (VI) and revealed 1.2 to 2.8 times more chlorophyll in the presence of the metal. While phycobilins and carotenoids also increased in Nostoc linckia with total dissolved salts (TDS) as well as metal, a decline was observed in Nostoc spongiaeforme in the presence of Cr (VI). Relative algal biomass (as % of control) showed significantly higher values (123-239) in Nostoc linckia in the presence of salt, metal and combination of the two. In Nostoc spongiaeforme it declined in the presence of metal (72-81) but increased in the presence of salts (143-249) and also in the binary systems (121-440). The bi-algal consortium showed relatively less tolerance to salt and metal stress. Nostoc linckia (20 day culture) showed upto 40% chromium removal whereas Nostoc spongiaeforme showed up to 12% removal, indicating greater suitability of the former for use in bioremediation studies.

Removal of fluoride by thermally activated carbon prepared from neem (Azadirachta indica) and kikar (Acacia arabica) leaves.

The present investigation deals with fluoride removal from aqueous solution by thermally activated neem (Azadirachta indica) leaves carbon (ANC) and thermally activated kikar (Acacia arabica) leaves carbon (AKC) adsorbents. In this study neem leaves carbon and kikar leaves carbon prepared by heating the leaves at 400 degrees C in electric furnace was found to be useful for the removal of fluoride. The adsorbents of 0.3 mm and 1.0 mm sizes of neem and kikar leaves carbon was prepared by standard sieve. Batch experiments done to see the fluoride removal properties from synthetic solution of 5 ppm to study the influence of pH, adsorbent dose and contact time on adsorption efficiency The optimum pH was found to be 6 for both adsorbents. The optimum dose was found to be 0.5g/100 ml forANC (activated neem leaves carbon) and 0.7g/100 ml forAKC (activated kikar leaves carbon). The optimum time was found to be one hour for both the adsorbent. It was also found that adsorbent size of 0.3 mm was more efficient than the 1.0 mm size. The adsorption process obeyed Freundlich adsorption isotherm. The straight line of log (qe-q) vs time at ambient temperature indicated the validity of langergren equation consequently first order nature of the process involved in the present study. Results indicate that besides intraparticle diffusion there maybe other processes controlling the rate which may be operating simultaneously. All optimized conditions were applied for removal of fluoride from four natural water samples.

Equilibrium sorption isotherm studies of Cd(II), Pb(II) and Zn(II) ions detoxification from waste water using unmodified and EDTA-modified maize husk

The mobilization of heavy metals in the environment due to industrial activities is of serious concern due to the toxicity of these metals in humans and other forms of life. The equilibrium adsorption isotherms of Cd(II), Pb(II) and Zn(II) ions, detoxification from waste water using unmodified and EDTA-modified maize husk have been studied. Maize husk was found to be an excellent adsorbent for the removal of these metal ions. The amount of these metal ions adsorbed increased as the initial concentration increased. Also, EDTA-modification enhanced the adsorption capacity of maize husk due to the chelating ability of ethylenediamine tetra acetic acid (EDTA). Among the three adsorption isotherms tested, Dubinin-Radushkevich isotherm gave the best fit with R² value ranging from 0.7646 to 0.9988 and an average value of 0.9321. This is followed by Freundlich and then Langmiur isotherms. The sorption process was found to be mostly a physiosorption process as seen from the apparent energy of adsorption which ranged from 1.03 KJ/mol to 12.91 KJ/mol. Therefore, this study demonstrates that maize husk which is an environmental pollutant could be used to adsorb heavy metals and achieve environmental cleanliness.

Textile anionic dyes recovery using tri-n-butyl phosphate as carrier through supported liquid membrane.

The recovery of anionic dyes Acid Red10 B (CI Acid Violet 54) and Acid Pink BE (CI Acid Red 183) in flat type supported liquid membrane (SLM) using tri-n-butyl phosphate as carrier was studied. The parameters studied were the effect of feed phase pH, stripping reagent concentration, string speed and initial dye concentration on permeability of dyes. The influence of salt concentration such as sodium chloride and sodium sulphate on the dye recovery was examined. The reusability of membrane and kinetics of transport were also studied. The optimum conditions of transport are feed phase pH 1 +/- 0.1, 0.1 M sodium hydroxide as stripping phase, stirring speed at 500 rpm. The maximum recovery under optimum conditions was observed as 94.2 % for Acid Red10 B and 85.7 % for Acid Pink BE. The maximum permeability was 11.0 x 10(-6) m/s for Acid Red10 B and 7.7 x 10(-6) m/s for Acid Pink BE.

Performance evaluation of an anaerobic baffled reactor treating wheat flour starch industry wastewater

Feasibility of the anaerobic baffled reactor process was investigated for the treatment of wheat flour starch wastewater. After removal of suspended solids by simple gravity settling, starch wastewater was used as a feed. Start-up of a reactor [with a volume of 13.5 L and five compartments] with diluted feed of approximately 4500 mg/L chemical oxygen demand was accomplished in about 9 weeks using seed sludge from anaerobic digester of municipal wastewater treatment plant. The reactor with hydraulic retention time of 72h at 35°C and initial organic loading rate of 1.2 kgCOD/m3.d showed 61% COD removal efficiency. The best performance of reactor was observed with an organic loading rate of 2.5 kgCOD/m3.d or hydraulic retention time of 2.45 d and the COD conversion of 67% was achieved. The system also showed very high solids retention with effluent suspended solids concentration of about 50 mg/L for most organic and hydraulic loadings studied. Based on these observations, the ABR process has potential to treat food industrial wastewater as a pretreatment and is applicable for extreme environmental conditions

Removal of arsenic from an aqueous solution by pretreated waste tea fungal biomass

Arsenic contamination in water poses a serious threat on human health. The tea fungus known as Kombucha is a waste produced during black tea fermentation. The objective of this study was to examine the main aspect of a possible strategy for the removal of arsenates employing tea fungal biomass. The pretreatment of biomass with FeCl3 was found to improve the biosorption efficiency. Arsenics uptake was found to be rapid for all concentrations and reached to 79% of equilibrium capacity of biosorption in 20 min and reached equilibrium in 90 min. The pseudo second-order and first-order models described the biosorption kinetics of As [V] with good correlation coefficient [R2>0.93] and better than the other equations. The data obtained from the experiment of biosorption isotherm were analyzed using the Freundlich and Langmuir isotherm models. The equation described the isotherm of As [V] biosorption with relatively high correlation coefficient [R2>0.93]. According to the Langmuir model, the maximum uptake capacities [qm] of tea fungal biomass for As [V] were obtained 3.98 +/- 10-3 mmol/gr. The effect of Na+, K+, Mg+2 and Ca+2 on equilibrium capacities of As was not significant. The variation of sorption efficiency with pH showed that optimum biosorption takes place in the pH ranges of 6 to 8. Promising results were obtained in laboratory experiments and effective As [V] removals were observed