Uptake of metal ions by chemically treated human hair

The uptake capacity of chemically treated human hair waste for the various metal ions can be arranged in the following decreasing order: Hg²⁺ (Hg⁺), Ag⁺, Pb²⁺, Cd²⁺, Cu²⁺ (Cu⁺), Cr⁶⁺, Ni²⁺, Cr³⁺.The uptake capacity is significantly affected by the presence of other metal ions. Anionic effect was found to be more pronounced for a mixed ions system than for a single ion system.     

Synthesis,characterisation and application of new tamarind triethylamine (TTEA) resin for removal of toxic metal ions from the effluent of Puneet Steel Industry,Jodhpur, Rajasthan

A new ion exchange resin tamarind triethylamine (TTEA) was chemically synthesised by modified Porath's method of functionalisation of polysaccharides. The prepared resin was characterised on the basis of ion exchange capacity, elemental analysis, Fourier transform infrared (FTIR) spectra and thermogravimetric analysis (TGA). Chemical resistivity of TTEA resin was assessed in several acidic, basic media. The present method is simple and rapidly applicable for the removal and recovery of metal ions from effluent of industries. The distribution coefficient (K _d) values of metal ions have been determined by batch method. Owing to the large differences in K _d values of toxic metal ions at different pH, removal and recovery of metal ions from their aqueous solutions and effluent of Puneet Steel Industry, Jodhpur has been studied systematically. The adsorption of different metal ions on TTEA resin follows the order; Fe²⁺ > Zn²⁺ > Cu²⁺ > Pb²⁺ > Cd²⁺. The Ion exchange capacity (IEC) of TTEA resin was 2.04%.     

Studies on the use of inorganic gels in the removal of heavy metals

Chromium ferrocyanide gel shows a great affinity for Ag⁺, Cu²⁺, Tl⁺, Zn²⁺, Co²⁺, Cd²⁺, Mn²⁺ and Fe³⁺ and has been used to separate and recover some heavy metal ions viz. Tl⁺, Hg²⁺, Mg²⁺, Fe³⁺ etc. Some of these can be completely eluted from the columns of this exchanger material and the compound can be used to treat waste water rich in heavy metal ions.     

The sorption of copper(II), manganese(II), zinc(II) and arsenic(III) onto human hair,and their desorption

Human hair has been studied in relation to sorption from aqueous solutions of Cu²⁺, Mn²⁺, Zn²⁺ and AsO₃^3?. At an equilibrium concentration of 0.3 μg ml^?1 the sorptions are relatively low for Mn (1.1 μg g^?1) and As (0.1 μg g^?1), and higher for Zn (10 μg g^?1) and Cu (35 μg g^?1). But only in the case of copper is the sorption significant relative to the indigenous levels of the elements in the hair. The greater sorption of Cu²⁺ may be correlated with better binding to the hair fibre, probably both electrostatically and to the sulphur in the keratin. There appears to be at least three modes of attachment, or three mechanisms of attachment of Cu²⁺ to the hair. An inter-element effect was observed, where Cu²⁺ severely inhibits the sorption of Zn²⁺ and Mn²⁺. Also the total sorption of Cu²⁺ is reduced on zinc or manganese-treated hair. Some comments are made regarding the results and the problems of exogenous contamination of human hair.     

Redox control in breakpoint chlorination of ammonia and metal ammine complexes

Redox control of breakpoint chlorination of ammonia and metal ammine complexes (Cu²⁺, Ni²⁺, Cr³⁺, Zn²⁺, Cd²⁺) is investigated. In simulated waste streams it is shown that at pH 8 control is feasible with a large (400 mV) and reproducible increase in the potential of a gold or platinum indicator electrode occurring at the breakpoint. At pH 10 control is less practicable due to the slowness of response, irreproducibility and smaller magnitude of the potential change. Simultaneous pH control is critical.     

Heavy metal accumulation by aquatic fungi and reduction in viability of Gammarus pulex fed Cd contaminated mycelium

The addition of Pb²⁺ (1.0 and 2.5 μg ml⁻¹) and Cd²⁺ (2.5 and 5.0 μg ml⁻¹) to growth medium decreased the growth of aquatic fungi, while Zn²⁺ even at a concentration of 10 μg ml⁻¹ had no inhibitory effect. Low concentrations of Cd²⁺ and Zn²⁺ on the other hand stimulated mycelial growth. The fungi accumulated considerable amounts of metal from the growth medium, generally in the order Zn²⁺ > Pb²⁺ > Cd²⁺ · Cd²⁺ was also accumulated by fungi from successive changes of medium containing low concentrations of the metal. Application of Langmuir and Freundlich isotherms to the results showed that the metals were accumulated largely by adsorption to the surface of the mycelium.Three species of aquatic fungi supported the growth of the freshwater shrimp. Gammarus pulex when provided as sole food source, sustaining from 30 to 60% of shrimps fed for a period of 21 days. A marked reduction in shrimp viability occurred however, when G. pulex was fed Pythium sp. containing Cd²⁺ (150–170 μg g⁻¹), with none of the shrimps surviving beyond 13 days, compared with a survival rate of 60% after 21 days for shrimps fed uncontaminated mycelium. Bodies of poisoned shrimps sampled on day 13 were found to contain Cd²⁺ (22.03 μg g⁻¹) showing that the metal can be transferred from aquatic fungi to G. pulex, the first step in a food chain involving freshwater fish and higher organisms.     

Influences of pH, heavy metals and phosphate and their co-influences on the sorption of pentachlorophenol on cyanobacterial biomass

Influences of pH, two types of ions of transition metals (Cu²⁺, Cd²⁺), Na₃PO₄ and their co-influences on the sorption of pentachlorophenol (PCP) on cyanobacterial biomass derived from natural bloom were studied. Sorption of PCP significantly decreases with pH in the range of 3.25-9.00. Although sorption coefficient of ionized PCP is 8.51 times lower than that of neutral species, it is the dominant species at environmentally relevant pH and contributes more to the total sorption of PCP. In the presence of low concentration of Cu²⁺ (≤40 μmol L⁻¹), sorption of PCP was much lower than that of the blank. However, it increased gradually with Cu²⁺, and overpassed the blank when concentration of Cu²⁺ was higher than 50 μmol L⁻¹. Compared with the sole influence of pH, coexisted Cu²⁺ inhibited the sorption of PCP at pH of 3.25 and 4.35, but enhanced it in the pH range of 5.00-9.00. In the presence of Cd²⁺, sorption of PCP first increased then decreased rapidly and finally increased slightly again with Cd²⁺. Except for at pH of 9.00, sorption of PCP at other pH in the presence of Cd²⁺ was much lower than that solely affected by pH. In the presence of Na₃PO₄, sorption of PCP increased rapidly then maintained with Na₃PO₄. Under the influence of both Na₃PO₄ and pH, sorption of PCP at pH from 3.25 to 5.00 was lower than that solely affected by pH, while it increased with pH in the range of 5.00-9.00 and was higher than that solely affected by pH in the range of 6.00-9.00. Ion pairs of pentachlorophenolate-metal facilitated the sorption of PCP, which was largely dependent on pH illustrated by UV-visible and FTIR spectra. Speciations of metals and PCP and the stability constants of ion pairs of pentachlorophenolate-metal greatly affected the sorption. Ionic strength also played an important role for the sorption of PCP.     

Batch metal removal by peat. Kinetics and thermodynamics

Peat moss, a natural inexpensive material, is able to play an important rôle in treatment processes of metal-bearing industrial effluents since it adsorbs, complexes or exchanges various metal cations. This paper presents kinetics and thermodynamics of batch metal removal reactions by 50 g l⁻¹ (dry wt) eutrophic or oligotrophic peat particles using Cu²⁺, Cd²⁺, Zn²⁺ and Ni²⁺ concentrations ranging from 0.01 to 100 mM.Metal cation removal reactions are moderately rapid in 10 mM metal unbuffered solutions: the forward kinetic constant ranges between 0.005 and 0.17 M⁻¹s⁻¹, and equilibrium is reached within about 1 h. Under these conditions of pH (2.2–4.2) and concentrations, apparent binding equilibrium constants were found to range between 2 and 3150 M⁻¹ depending upon the peat origin and the metal cation.In 0–6.5 pH-buffered metal cation solutions, the four cations binding reactions behaved differently demonstrating that metal binding equilibrium constant decrease in the order Ni²⁺ > Cu²⁺ > Cd²⁺ = Zn²⁺. When pH is higher than 6.7, more than 90% of a 10 mM metal cation solution is removed by 50 g 1⁻¹ peat particles and metal binding capacities equal 200 mmol kg⁻¹ dry wt, whatever the metal nature and the peat origin. Except for nickel cation which is very strongly bound to peat, all metal cations are completely released when pH is fixed below 1.5.     

A survey of tap water quality in Kuala Lumpur

A safe drinking water programme known as The National Drinking Water Quality Surveillance Programme (NDWQSP) was launched by the Ministry of Health, Government of Malaysia in 1983 to ensure safe practices in water treatment and distribution. The aim of this work was to assess the effectiveness of this programme in the improvement of tap water quality in and around Kuala Lumpur. The results indicate that there was no microbial contamination in 100 random samples collected from 20 selected areas. Other quality parameters such as colour, pH, turbidity, hardness, magnesium, sulphate and chloride were within acceptable limits. Heavy metals such as Cu²⁺, Pb²⁺, Cr (total), Ni²⁺, Cd²⁺, Fe (total) and Mn (total) were also under control. The only exception was Ba²⁺, which did not comply with the standard and was up to ten times higher than the guideline value. Moreover, there was significant variation in water quality as indicated by the test results.     

Ulva prolifera (Chlorophyta): a suitable material to remove Cd2+ from aquatic environments

Heavy metal pollution in aquatic environments is a significant environmental problem. Marine macroalgae are novel materials for the removal of heavy metals from water, aided by their large biomass and the feature of easy collection. In this study, Ulva prolifera O.F.Müller was used to remove cadmium ions (Cd²⁺) from the aquatic environment. We examined the Cd²⁺ absorption capacity of the thalli in a factorial experiment using fresh thalli cultivated in seawater, freshwater, water containing domestic garbage, water containing industrial waste and elutriant of soil with additional Cd²⁺. In addition, changes in photosynthetic activity of thalli were investigated. A significant decrease of maximum quantum yield and effective photochemical quantum yield of PSII (YII) indicated Cd²⁺ was transported into the cells and seriously inhibited photosynthesis. Furthermore, the Cd²⁺ absorption capacity was relatively high. The results indicated the suitability of U. prolifera for removing Cd²⁺ from aquatic environments of different backgrounds.     

Heavy metal accumulation by aquatic fungi and reduction in viability of Gammarus pulex fed Cd2+ contaminated mycelium

The addition of Pb²⁺ (1.0 and 2.5 μg ml^?1) and Cd²⁺ (2.5 and 5.0 μg ml^?1) to growth medium decreased the growth of aquatic fungi, while Zn²⁺ even at a concentration of 10 μg ml^?1 had no inhibitory effect. Low concentrations of Cd²⁺ and Zn²⁺ on the other hand stimulated mycelial growth. The fungi accumulated considerable amounts of metal from the growth medium, generally in the order Zn²⁺ > Pb²⁺ > Cd²⁺ · Cd²⁺ was also accumulated by fungi from successive changes of medium containing low concentrations of the metal. Application of Langmuir and Freundlich isotherms to the results showed that the metals were accumulated largely by adsorption to the surface of the mycelium.Three species of aquatic fungi supported the growth of the freshwater shrimp. Gammarus pulex when provided as sole food source, sustaining from 30 to 60% of shrimps fed for a period of 21 days. A marked reduction in shrimp viability occurred however, when G. pulex was fed Pythium sp. containing Cd²⁺ (150–170 μg g^?1), with none of the shrimps surviving beyond 13 days, compared with a survival rate of 60% after 21 days for shrimps fed uncontaminated mycelium. Bodies of poisoned shrimps sampled on day 13 were found to contain Cd²⁺ (22.03 μg g^?1) showing that the metal can be transferred from aquatic fungi to G. pulex, the first step in a food chain involving freshwater fish and higher organisms.     

重金属污染土物理性质强度定量关系试验研究

通过室内试验研究土体孔隙液中重金属离子影响土体物理力学性状的机理,采用不同浓度的重金属Cu2+、Zn2+、Pb2+掺入高岭土、伊利石类黏土和钠基膨润土,研究土体界限含液率、不排水抗剪强度随重金属离子浓度的变化规律。试验结果表明:以高岭石、伊利石为主要黏土矿物的低活性土的液限、塑性指数随离子浓度的增加而增大,钠基膨润土则表现出相反的变化规律;低活性黏土的不排水抗剪强度随离子浓度增加而增大,高活性黏土强度则随之减小;基于已有的无污染土体物理力学性状定量联系,分析重金属污染土的不排水抗剪强度与液性指数的定量关系,发现重金属离子引起的不排水抗剪强度的变化可以归结于重金属离子引起的液塑限变化,表明重金属Cu2+、Zn2+、Pb2+污染过程基本没有产生化学反应,其物理力学定量关系与已有的无污染土经验关系式一致。     

Water purification from metal ions using carbon nanoparticle-conjugated polymer nanocomposites

The paper deals with a novel method of obtaining nanocarbon-conjugated polymer nanocomposites (NCPC) using nanocarbon colloids (NCC) and polyethylenimine (PEI) for water purification from metal ions. Size of NCC, process of NCPC synthesis, its chemical characteristics, ratio of NCC and PEI in NCPC, speed of coagulation of NCPC, mechanism of interaction of metal ions with NCPC, ability of removing metal ions from water by NCPC against pH have been studied. NCPC has a bonding capacity of 4.0-5.7 mmol/g at pH 6 for most of the divalent metal ions. Percent of sorption of Zn²⁺, Cd²⁺, Cu²⁺, Hg²⁺, Ni²⁺, Cr⁶⁺ ions is higher than 99%. Lifetime of NCPC before coagulation in the treated water is 1 s-1000 min and depends on the ratio of polymeric molecules and carbon nanoparticle concentrations. Results of laboratory tests of the method are described.     

Heavy metal removal in anaerobic semi-continuous stirred tank reactors by a consortium of sulfate-reducing bacteria

Removal of heavy metals by an enriched consortium of sulfate-reducing bacteria (SRB) was evaluated through the abundance of SRB, sulfate reduction, sulfide production and heavy metal precipitation. Five parallel anaerobic semi-continuous stirred tank reactors (CSTR, V = 2 L) (referred as R1-R5) were fed with synthetic wastewater containing mixtures of Cu²⁺, Zn²⁺, Ni²⁺, and Cr⁶⁺ in the concentrations of 30, 60, 90, 120, and 150 mg L⁻¹ of each metal and operated with a hydraulic retention time of 20 days for 12 weeks. The loading rates of each metal in R1-R5 were 1.5, 3, 4.5, 6, and 7.5 mg L⁻¹ d⁻¹, respectively. The results showed that there was no inhibition of SRB growth and that heavy metal removal efficiencies of 94-100% for Cu²⁺, Zn²⁺, Ni²⁺, and Cr⁶⁺ were achieved in R1-R3 throughout the experiment and in R4 during the first 8 weeks. The toxic effect of heavy metals on the SRB consortium was revealed in R5, in which no SRB could survive and almost no heavy metal precipitation was detected after four weeks of operation.     

Electrochemical speciation and determination of organometallic species in natural waters

A procedure is described based on selective organic-phase extraction coupled with differential pulse electrochemical techniques for the consecutive determination of Me₄Pb, Et₄Pb, Me₃Pb⁺, Et₃Pb⁺, Me₂Pb²⁺, Et₂Pb²⁺ and inorganic Pb²⁺, present in a water sample.     

Photodegradation of selected β-blockers in aqueous fulvic acid solutions: kinetics, mechanism, and product analysis

The photodegradation of the widely used β-blockers atenolol and metoprolol were investigated in the presence of fulvic acid (FA) under simulated sunlight. Both atenolol and metoprolol undergo indirect photodegradation in the FA solutions. The triplet excited state of FA (³FA^∗) was verified to be main reactive species responsible for the photosensitized degradation of β-blockers. An electron transfer mechanism for the interaction between β-blockers and ³FA^∗ was proposed on the basis of a series of experiments. Magnetic property of metal ions exhibited significant impact on photosensitized degradation. Diamagnetic metal ions such as Mg²⁺, Ca²⁺, Zn²⁺, and Al³⁺ negligibly affected the degradation. In contrast, paramagnetic metal ions including Mn²⁺, Cu²⁺, Fe³⁺, and Cr³⁺ markedly inhibited the reactions in the order of Cr³⁺ < Fe³⁺ < Cu²⁺ < Mn²⁺. The inhibition was related to the complexation ability with FA. By LC-ESI-MS/MS analysis, deisopropyl-atenolol (metoprolol) was identified as the main photosensitized product. The degradation pathways of β-blockers involving electron transfer processes were proposed. This finding strongly suggests that ³FA^∗ was important reactive species for the degradation of β-blockers in natural waters.     

A comparison of toxicity tests conducted in the laboratory and in experimental ponds using cadmium and the fathead minnow (Pimephales promelas)

Acute toxicity tests were conducted in the laboratory with fathead minnows (Pimephales promelas) to determine the 96-h LC₅₀ of cadmium under three conditions: (1) in laboratory water, (2) in water from experimental ponds, and (3) in pond water underlain by sediment. Cadmium was then applied at doses equivalent to the estimated LC₅₀ values to 0.07-ha ponds containing caged fathead minnows. A cadmium ion selective electrode, ultrafiltration, and equilibrium calculations were used to determine cadmium speciation, and several water quality characteristics were measured to correlate differences in mortality between test systems (laboratory and field) with observed differences in water quality. The LC₅₀ estimates (mg l⁻¹) for the bioassays were 4.39 for the laboratory water, 3.52 for the pond water with sediment, and 2.91 for the pond water. Concentrations of Cd²⁺ decreased and those of cadmium in the particulate (> 1.2 μm) and 300,000 mol. wt (0.018–1.2 μm) fractions increased over the 96-h; cadmium in these fractions was believed to consist of colloidal sized CdCO₃ precipitates. Concentrations of Cd²⁺ decreased at different rates between test systems, regulated by the degree of CdCO₃(s) supersaturation which in turn depended on pH and total metal concentrations. Differences in toxicity in the laboratory tests were attributed to differences in water hardness and Cd²⁺ concentrations. Mortality of fathead minnows was low (0–10%) during the 96-h test period in the ponds due to the higher pH, which produced supersaturated conditions resulting in the rapid formation of nontoxic CdCO₃ precipitates and a more rapid decrease in Cd²⁺ concentrations as compared to the laboratory bioassays.     

Metal sorption on blast-furnace slag

The removal of Cu, Ni and Zn-ions from water solution by ungranulated blast-furnace slag has been studied depending on contact time, initial ion concentration, pH and solution temperature. The polymineral composition and the slag specific properties determine its high sorption activity in metal salts solutions. In the range of the concentrations studied (10⁻⁴–10⁻³ M), the sorption data for Cu²⁺, Ni²⁺ and Zn²⁺ have been described using Freundlich's parabolic equation. The material's own alkalizing activity creates conditions for effective metal ions sorption in a wide pH range. With the temperature increase the hydrolysis of the sorption matrix intensifies which leads to the sorption improvement. On the basis of both literature data and the author's own data the mechanism of metal ions removed by blast-furnace slag has been discussed.     

The availability of cadmium to perfused rainbow trout gills in different water qualities

The uptake of cadmium in perfused gills from rainbow trout (Salmo gairdneri, Rich.) in different water qualities has been studied.In the naturally hard alkaline Uppsala tap water, the calcium concentration was the dominating factor controlling the cadmium transfer through the gills. A strong inverse relationship was measured between the external Ca²⁺ concentration up to 3 mmol l^?1 (< 120 mg Ca²⁺ l^?1), and the Cd transfer. A higher Ca²⁺ concentration (10 mmol l^?1) did not further affect the transfer. Magnesium decreased the transfer, but only at concentrations 4 to 5 times as high as calcium. At a constant Ca²⁺/Mg²⁺ hardness, the transfer was a function of the free cadmium ion activity (Cd²⁺). Ca²⁺ and Mg²⁺ selectively reduced the transfer by a biological mechanism, probably by changing the permeability of the gill epithelium.Cd transfer was not dependent on pH in the range pH 5–7. A lower transfer at pH 7.6 was related to a lower Cd²⁺ activity, probably due to the formation of non-available bicarbonate/carbonate complexes.Cd transfer decreased in the presence of 121 mmol l^?1 NaCl (0.7% salinity). This decrease was not caused by the altered osmotic gradient over the gills. The transfer was proportional to the Cd²⁺ activity. CdCl⁺ and CdCl₂ were not available for the gills.The retention of Cd in perfused gill tissue was proportional to the Cd²⁺ activity in all water qualities tested. Tissue accumulation of Cd was not sensitive to external Ca and Mg and in this respect different from the transfer.