棘孢曲霉（Aspergillus aculeatus）对Pb2＋和Cd2＋的吸附特征

为了研究棘孢曲霉（Aspergillus aculeatus）对溶液中Pb^2＋和Cd^2＋吸附过程的特征，分别从动力学、热力学和吸附等温线三方面进行了实验，同时还研究了pH、温度、时间、重金属离子起始浓度和吸附剂用量对吸附过程的影响。等温吸附过程可以用Langmuir方程来描述。在实验设定条件下，棘孢曲霉对Pb^2＋和Cd^2＋最大吸附量分别为71.2 mg/g和59.8 mg/g；动力学实验数据很好的符合二级     

Removal of Pb(II), Cd(II), Cu(II), and Zn(II) by hematite nanoparticles: effect of sorbent concentration, pH, temperature, and exhaustion

Nanoparticles offer the potential to improve environmental treatment technologies due to their unique properties. Adsorption of metal ions (Pb(II), Cd(II), Cu(II), Zn(II)) to nanohematite was examined as a function of sorbent concentration, pH, temperature, and exhaustion. Adsorption experiments were conducted with 0.05, 0.1, and 0.5 g/L nanoparticles in a pH 8 solution and in spiked San Antonio tap water. The adsorption data showed the ability of nanohematite to remove Pb, Cd, Cu, and Zn species from solution with adsorption increasing as the nanoparticle concentration increased. At 0.5 g/L nanohematite, 100 % Pb species adsorbed, 94 % Cd species adsorbed, 89 % Cu species adsorbed and 100 % Zn species adsorbed. Adsorption kinetics for all metals tested was described by a pseudo second-order rate equation with lead having the fastest rate of adsorption. The effect of temperature on adsorption showed that Pb(II), Cu(II), and Cd(II) underwent an endothermic reaction, while Zn(II) underwent an exothermic reaction. The nanoparticles were able to simultaneously remove multiple metals species (Zn, Cd, Pb, and Cu) from both a pH 8 solution and spiked San Antonio tap water. Exhaustion experiments showed that at pH 8, exhaustion did not occur for the nanoparticles but adsorption does decrease for Cd, Cu, and Zn species but not Pb species. The strong adsorption coupled with the ability to simultaneously remove multiple metal ions offers a potential remediation method for the removal of metals from water.     

Removal of Ni(II) and Cu(II) ions using native and acid treated Ni-hyperaccumulator plant Alyssum discolor from Turkish serpentine soil

Alyssum discolor biomass was collected from serpentine soil and was used for removal of metal ions. The plant species grown on serpentine soils are known to be rich with metals ions and thus have more capability for accumulating heavy metals. Native and acid-treated biomass of A. discolor (A. discolor) were utilized for the removal of Ni(II) and Cu(II) ions from aqueous solutions. The effects of contact time, initial concentration, and pH on the biosorption of Ni(II) and Cu(II) ions were investigated. Biosorption equilibrium was established in about 60 min. The surface properties of the biomass preparations were varied with pH, and the maximum amounts of Ni(II) and Cu(II) ions on both A. discolor biomass preparations were adsorbed at pH 5.0. The maximum biosorption capacities of the native, and acid-treated biomass preparations for Ni(II) were 13.1 and 34.7 mg g⁻¹ and for Cu(II) 6.15 and 17.8 mg g⁻¹ dry biomass, respectively. The biosorption of Ni(II) and Cu(II) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. When the heavy metal ions were in competition, the amounts of biosorbed metal ions on the acid treated plant biomass were found to be 0.542 mmol g⁻¹ for Ni(II) and 0.162 mmol g⁻¹ for Cu(II), the A. discolor biomass was significantly selective for Ni(II) ions. The information gained from these studies was expected to indicate whether the native, and acid-treated forms can have the potential to be used for the removal and recovery of Ni(II) ions from wastewaters.     

Simultaneous heavy metal removal mechanism by dead macrophytes

The use of dead, dried aquatic plants, for water removal of metals derived from industrial activities as a simple biosorbent material has been increasing in the last years. The mechanism of simultaneous metal removal (Cd2+, Ni2+, Cu2+, Zn2+ and Pb2+) by 3 macrophytes biomass (Spirodela intermedia, Lemna minor and Pistia stratiotes) was investigated. L. minor biomass presented the highest mean removal percentage and P. stratiotes the lowest for all metals tested. Pb2+ and Cd2+ were more efficiently removed by the three of them. The simultaneous metal sorption data were analysed according to Langmuir and Freundlich isotherms. Data fitted the Langmuir model only for Ni and Cd, but Freundlich isotherm for all metals tested, as it was expected. The K(F) values showed that Pb was the metal more efficiently removed from water solution. The adsorption process for the three species studied followed first order kinetics. The mechanism involved in biosorption resulted ion exchange between monovalent metals as counter ions present in the macrophytes biomass and heavy metal ions and protons taken up from water. No significant differences were observed in the metal exchange amounts while using multi-metal or individual metal solutions.     

Biosorption properties of zinc(II) from aqueous solutions by Pseudevernia furfuracea (L.) Zopf

Pseudevernia furfuracea (L.) Zopf biosorption efficiency for zinc(II) was determined. The biosorption efficiency of Zn(II) onto P. furfuracea was significantly affected by the parameters of pH, biomass concentration, stirring speed, contact time, and temperature. The maximum biosorption efficiency of P. furfuracea was 92% at 10 mg/L Zn(II), for 5 g/L lichen biomass dosage. The biosorption of Zn(II) ions onto biomass was better described by the Langmuir model and the pseudo-second-order kinetic. The obtained thermodynamic parameters from biosorption of Zn(II) ions onto biomass were feasible, exothermic, and spontaneous. The different desorbents were used to perform the desorption studies for Zn(II)-loaded biomass. Fourier transform infrared (FTIR) spectroscopy was used to determine the participating functional groups of P. furfuracea biomass in Zn (II) biosorption. The broad and strong bands at 3292–3304 cm^?1 were due to bound hydroxyl (–OH) or amine (–NH) groups. The effective desorptions were obtained up to 96% with HNO₃. P. furfuracea is an encouraging biosorbent for Zn(II) ions, with high metal biosorption and desorption capacities, availability, and low cost. It was believed that by using this new method in which biomass is used as a sorbent, the toxic pollutants could be selectively removed from aqueous solutions to desired low levels. The remarkable properties of lichens in the transformation and detoxification of organic and inorganic pollutants are well known, and many processes have received attention in the general area of environmental biotechnology and microbiology.

Implications:The remarkable properties of lichens in the biosorption capacity of organic and inorganic pollutants are well known, and many processes have received attention in the general area of environmental biotechnology and microbiology.     

棘孢曲霉(Aspergillus aculeatus)对Pb~(2+)和Cd~(2+)的吸附特征

为了研究棘孢曲霉(Aspergillus aculeatus)对溶液中Pb~(2+)和Cd~(2+)吸附过程的特征,分别从动力学、热力学和吸附等温线三方面进行了实验,同时还研究了pH、温度、时间、重金属离子起始浓度和吸附剂用量对吸附过程的影响。等温吸附过程可以用Langmuir方程来描述。在实验设定条件下,棘孢曲霉对Pb~(2+)和Cd~(2+)最大吸附量分别为71.2 mg/g和59.8 mg/g;动力学实验数据很好的符合二级动力学方程,吸附达到平衡的时间为3 h;热力学实验数据显示该吸附过程为自发的、吸热的过程。     

Microbial indicators of heavy metal contamination in urban and rural soils

Urban soils and especially their microbiology have been a neglected area of study. In this paper, we report on microbial properties of urban soils compared to rural soils of similar lithogenic origin in the vicinity of Aberdeen city. Significant differences in basal respiration rates, microbial biomass and ecophysiological parameters were found in urban soils compared to rural soils. Analysis of community level physiological profiles (CLPP) of micro-organisms showed they consumed C sources faster in urban soils to maintain the same level activity as those in rural soils. Cu, Pb, Zn and Ni were the principal elements that had accumulated in urban soils compared with their rural counterparts with Pb being the most significant metal to distinguish urban soils from rural soils. Sequential extraction showed the final residue after extraction was normally the highest proportion except for Pb, for which the hydroxylamine-hydrochloride extractable Pb was the largest part. Acetic acid extractable fraction of Cd, Cu, Ni, Pb and Zn were higher in urban soils and aqua regia extractable fraction were lower suggesting an elevated availability of heavy metals in urban soils. Correlation analyses between different microbial indicators (basal respiration, biomass-C, and sole C source tests) and heavy metal fractions indicated that basal respiration was negatively correlated with soil Cd, Cu, Ni and Zn inputs while soil microbial biomass was only significantly correlated with Pb. However, both exchangeable and iron- and manganese-bound Ni fractions were mostly responsible for shift of the soil microbial community level physiological profiles (sole C source tests). These data suggest soil microbial indicators can be useful indicators of pollutant heavy metal stress on the health of urban soils.     

Pre-concentration and separation of heavy metal ions by chemically modified waste paper gel

Iminodiacetic acid was immobilized on waste paper by chemical modification in order to develop a new type of adsorption gel for heavy metal ions. Adsorption behavior of the gel was investigated for a number of metal ions, specifically Cu(II), Pb(II), Fe(III), Ni(II), Cd(II), and Co(II) at acidic pH. From batch adsorption tests, the order of selectivity was found to be as follows: Cu(II)  Fe(III) > Pb(II) > Ni(II)  Co(II) > Cd(II). Column tests were carried out for pairs of metal ions to understand the separation and pre-concentration behavior of the gel. It was found that mutual separation of Ni(II) from Co(II) and that of Pb(II) from Cd(II) can be achieved at pH 3. Similarly, selective separation of Cu(II) from Cu(II)–Fe(III) and Cu(II)–Pb(II) mixtures at pH 1.5 and 2, respectively, was observed by using this new adsorption gel. In all cases, almost complete recovery of the adsorbed metal was confirmed by elution tests with HCl.     

Isotherms and sequential extraction procedures for evaluating sorption and distribution of heavy metals in soils

Heavy metals are potentially toxic to human life and the environment. Their contaminating effect in soils depends on chemical associations. Hence, determining the chemical form of a metal in soils is important to evaluate its mobility and bioavailability. We utilized a sequential extraction procedure and sorption isotherms (monometal and competitive) to evaluate the mobility and distribution of Cd, Cu, Ni, Pb, and Zn in four soils differing in their physicochemical properties: Calcixerollic Xerochrepts (Cx1 and Cx2), Paralithic Xerorthent (Px) and Lithic Haplumbrept (Lh). Most of the metals retained under point B conditions of sorption isotherms were extracted from the more mobile fractions: exchangeable and carbonates, in contrast with the profiles of the original soils where metals were preferently associated with the residual fraction. In soils having carbonate concentration under 6% (Cx1 and Lh), the exchangeable fraction was predominant, whereas in calcareous soils (Cx2 and Px) metals extracted from carbonates predominated. Partitioning profiles were in accordance with the affinity sequences deduced from the initial slope of isotherms and showed that the soils had a greater number of surface sites and higher affinity for Pb and Cu than for Cd, Ni, or Zn. In general, the simultaneous presence of the cations under study increased the percentages of metals released in the exchangeable fraction. The tendency towards less specific forms was more noticeable in Cx2 and Px soils and for Ni, Zn, and Cd. The affinity of inorganic surfaces was larger for Zn than for Cd or Ni, but the affinity of organic surfaces was larger for Cd or Ni than for Zn.     

Biosorption of nickel(II) from aqueous solution by Aspergillus niger: Response surface methodology and isotherm study

In the present study, the effects of biosorbent Aspergillus niger dosage, initial solution pH and initial Ni(II) concentration on the uptake of Ni(II) by NaOH pretreated biomass of A. niger from aqueous solution were investigated. Batch experiments were carried out in order to model and optimize the biosorption process. The influence of three parameters on the uptake of Ni(II) was described using a response surface methodology (RSM) as well as Langmuir and Freundlich isotherm models. Optimum Ni(II) uptake of 4.82 mg Ni(II) g⁻¹ biomass (70.30%) was achieved at pH 6.25, biomass dosage of 2.98 g L⁻¹ and initial Ni(II) concentration of 30.00 mg L⁻¹ Ni(II). Langmuir and Freundlich were able to describe the biosorption isotherm fairly well. However, prediction of Ni(II) biosorption using Langmuir and Freundlich isotherms was relatively poor in comparison with RSM approaches. The biosorption mechanism was also investigated by using Fourier transfer infrared (FT-IR) analysis of untreated, NaOH pretreated, and Ni(II) loaded A. niger biomass.     

Heavy metals in coastal wetland sediments of the Pearl River Estuary, China

Sediment quality in coastal wetlands of the Pearl River Estuary was concerned since the wetlands were used for land reclamation, aquaculture and wildlife protection, and meanwhile served as one of the main ultimate sinks for large amount of heavy metals discharged from the rapidly developing Pearl River Delta. Total concentrations of heavy metal, such as Zn, Ni, Cr, Cu, Pb, and Cd, and their chemical speciation were investigated. Results showed that the sediments were significantly contaminated by Cd, Zn and Ni with concentration ranges of 2.79-4.65, 239.4-345.7 and 24.8-122.1mg/kg, respectively. A major portion (34.6-46.8%) of Pb, Cd, and Zn was strongly associated with exchangeable fractions, while Cu, Ni and Cr were predominantly associated with organic fractions, residual, and Fe-Mn oxide. Cd and Zn would be the main potential risk and the sediment quality is no longer meeting the demand of the current wetland utilization strategies.     

棘孢曲霉（Aspergillus aculeatus）对Pb^2＋和Cd^2＋的吸附特征

为了研究棘孢曲霉（Aspergillus aculeatus）对溶液中Pb^2＋和Cd^2＋吸附过程的特征，分别从动力学、热力学和吸附等温线三方面进行了实验，同时还研究了pH、温度、时间、重金属离子起始浓度和吸附剂用量对吸附过程的影响。等温吸附过程可以用Langmuir方程来描述。在实验设定条件下，棘孢曲霉对Pb^2＋和Cd^2＋最大吸附量分别为71．2mg／g和59．8mg／g；动力学实验数据很好的符合二级动力学方程，吸附达到平衡的时间为3h；热力学实验数据显示该吸附过程为自发的、吸热的过程。     

Evaluation of different isotherm models,kinetic, thermodynamic,and copper biosorption efficiency of Lobaria pulmonaria (L.) Hoffm.

The biosorption characteristics of Cu(II) ions from aqueous solution using Lobaria pulmonaria (L.) Hoffm. biomass were investigated. The biosorption efficiency of Cu(II) onto biomass was significantly influenced by the operating parameters. The maximum biosorption efficiency of L. pulmonaria was 65.3% at 10 mg/L initial metal concentration for 5 g/L lichen biomass dosage. The biosorption of Cu(II) ions onto biomass fits the Langmuir isotherm model and the pseudo-second-order kinetic model well. The thermodynamic parameters indicate the feasibility and exothermic and spontaneous nature of the biosorption. The effective desorption achieved with HCl was 96%. Information on the nature of possible interactions between the functional groups of the L. pulmonaria biomass and Cu(II) ions was obtained via Fourier transform infrared (FTIR) spectroscopy. The results indicated that the carboxyl (–COOH) and hydroxyl (–OH) groups of the biomass were mainly involved in the biosorption of Cu(II) onto L. pulmonaria biomass. The L. pulmonaria is a promising biosorbent for Cu(II) ions because of its availability, low cost, and high metal biosorption and desorption capacities.

Implications: Lobaria pulmonaria is a promising biosorbent for Cu(II) ions because of its availability, low cost, and high metal biosorption and desorption capacities. To the best of our knowledge, this is the first paper on the biosorption Cu by L. pulmonaria.     

Changes in speciation and leaching behaviors of heavy metals in dredged sediment solidified/stabilized with various materials

Solidification/stabilization (S/S) of sediments is frequently used to treat contaminants in dredged sediments. In this study, sediment collected from the Pearl River Delta (China) was solidified/stabilized with three different kinds of functional materials: cement, lime and bentonite. Lime primarily acted via induced increases in pH, while cements stabilization occurred through their silicate-based systems and the main function of bentonite was adsorption. The speciation and leaching behaviors of specific heavy metals before and after S/S were analyzed and the results showed that the residual speciation of Cd, Cr, Ni, Pb and Zn increased in all treatments except for Cu, as the exchangeable speciation, carbonate-bound speciation and Fe-Mn-oxide-bound speciation of Cu (all of which could be stabilized) were less than 2 % of the total amount. Pb leaching only decreased when pH increased, while the mobility of Cr and Ni only decreased in response to the silicate-based systems. The leached portion of the Fe-Mn-oxide-bound speciation followed the order Zn?>?Cu?>?Ni/Cd?>?Pb?>?Cr. The leached portion of organic-matter-bound species was less than 4 % for Cd, Cr, Ni and Pb, but 35.1 % and 20.6 % for Cu and Zn, respectively.     

Evaluating three trace metal contaminated sites: a field and laboratory investigation

Selecting guidelines to evaluate elevated metals in urban brownfields is hindered by the lack of information for these sites on ecosystem structure and function. A study was performed to compare three trace metal-contaminated sites in the metropolitan Montreal area. The goal was to obtain an idea of the organisms that may be present on urban brownfields and to measure if elevated metals alter the presence and activity of the indigenous biota. Field and laboratory studies were conducted using simple methodologies to determine the extent to which microbial activity affected by trace metal content, to assess diversity of plant and soil invertebrate communities and to measure phytoaccumulation of trace metals. It was found that microbial activity, as measured by substrate-induced respiration (SIR) and nitrification, was not affected by the levels of soil Cd, Cu, Ni, Pb and Zn recorded on the sites. Seven of the 12 invertebrate groups collected were sampled on soils with similar Cd, Cu, Ni, Pb and Zn concentrations. Diversity of plant species increased as a function of the length of time the sites had been inactive. Levels of metals in plant tissue were influenced by soil characteristics and not by total soil Cd, Cu, Ni, Pb and Zn.     

Interaction effects of metals and salinity on biodegradation of a complex hydrocarbon waste

The presence of high levels of salts because of produced brine water disposal at flare pits and the presence of metals at sufficient concentrations to impact microbial activity are of concern to bioremediation of flare pit waste in the upstream oil and gas industry. Two slurry-phase biotreatment experiments based on three-level factorial statistical experimental design were conducted with a flare pit waste. The experiments separately studied the primary effect of cadmium [Cd(II)] and interaction effect between Cd(II) and salinity and the primary effect of zinc [Zn(II)] and interaction effect between Zn(II) and salinity on hydrocarbon biodegradation. The results showed 42-52.5% hydrocarbon removal in slurries spiked with Cd and 47-62.5% in the slurries spiked with Zn. The analysis of variance showed that the primary effects of Cd and Cd-salinity interaction were statistically significant on hydrocarbon degradation. The primary effects of Zn and the Zn-salinity interaction were statistically insignificant, whereas the quadratic effect of Zn was highly significant on hydrocarbon degradation. The study on effects of metallic chloro-complexes showed that the total aqueous concentration of Cd or Zn does not give a reliable indication of overall toxicity to the microbial activity in the presence of high salinity levels.     

The sequestration of trace elements by willow (Salix purpurea)—which soil properties favor uptake and accumulation?

The effect of soil properties on trace element (TE) extraction by the Fish Creek willow cultivar was assessed in a 4-month greenhouse experiment with two contrasted soils and two mycorrhizal treatments (Rhizophagus irregularis and natives). Aboveground tissues represented more than 82 % of the willow biomass and were the major sink for TE. Cadmium and Zn were concentrated in leaves, while As, Cu, Ni, and Pb were mostly found in roots. Willow bioconcentration ratios were below 0.20 for As, Cu, Ni, and Pb and reached 10.0 for Cd and 1.97 for Zn. More significant differences in willow biomass, TE concentrations, and contents were recorded between soil types than between mycorrhizal treatments. A slight significant increase in Cu extraction by willow in symbiosis with Rhizophagus irregularis was observed and was linked to increased shoot biomass. Significant regression models between TE in willow and soil properties were found in leaves (As, Ni), shoots (As, Cd, Cu, Ni), and roots (As, Cu, Pb). Most of the explanation was shared between soil water-soluble TE and fertility variables, indicating that TE phytoextraction is related to soil properties. Managing interactions between TE and major nutrients in soil appeared as a key to improve TE phytoextraction by willows.     

Interaction Effects of Metals and Salinity on Biodegradation of a Complex Hydrocarbon Waste

Abstract

The presence of high levels of salts because of produced brine water disposal at flare pits and the presence of metals at sufficient concentrations to impact microbial activity are of concern to bioremediation of flare pit waste in the upstream oil and gas industry. Two slurry-phase biotreatment experiments based on three-level factorial statistical experimental design were conducted with a flare pit waste. The experiments separately studied the primary effect of cadmium [Cd(II)] and interaction effect between Cd(II) and salinity and the primary effect of zinc [Zn(II)] and interactioneffect between Zn(II) and salinity on hydrocarbon biodegradation. The results showed 42–52.5% hydrocarbon removal in slurries spiked with Cd and 47–62.5% in the slurries spiked with Zn. The analysis of variance showed that the primary effects of Cd and Cd–salinity interaction were statistically significant on hydrocarbon degradation. The primary effects of Zn and the Zn-salinity interaction were statistically insignificant, whereas the quadratic effect of Zn was highly significant on hydrocarbon degradation. The study on effects of metallic chloro-complexes showed that the total aqueous concentration of Cd or Zn does not give a reliable indication of overall toxicity to the microbial activity in the presence of high salinity levels.     

Role of microbial inoculation and chitosan in phytoextraction of Cu, Zn, Pb and Cd by Elsholtzia splendens--a field case

A field experiment was carried out to study the effect of microbial inoculation on heavy metal phytoextraction by Elsholtzia splendens and whether chitosan could have a synergistic effect with the microbial inocula. The microbial inocula consisted of a consortium of arbuscular mycorrhizal fungi and two Penicillium fungi. Three treatments were included: the control, inoculation with microbial inocula, and the inoculation combined with chitosan. Microbial inoculation increased plant biomass especially shoot dry weight, enhanced shoot Cu, Zn and Pb concentrations but did not affect Cd, leading to higher shoot Cu, Zn, Pb and Cd uptake. Compared with microbial inoculation alone, chitosan application did not affect plant growth but increased shoot Zn, Pb and Cd concentrations except Cu, which led to higher phytoextraction efficiencies and partitioning to shoots of Zn, Pb and Cd. These results indicated synergistic effects between microbial inocula and chitosan on Zn, Pb and Cd phytoextraction.     

Processes controlling metal transport and retention as metal-contaminated groundwaters efflux through estuarine sediments

Factors affecting the transport and retention of Cd, Cr, Cu, Ni, Pb and Zn in acidic groundwaters as they pass through estuarine sediments were investigated using column experiments. Acidic groundwaters caused the rapid dissolution of iron sulfide (AVS) and other iron and manganese phases from sediments that are important for metal binding and buffering. Metal breakthrough to overlying water occurred in the order of Ni>Zn>Cd>Cu>Cr/Pb. Metal transport increased as the sediment permeability increased, reflecting the low resistance to flow caused by larger sand-sized particles and the decreased abundance of metal adsorption sites on these materials. Metal mobility increased as the groundwater pH decreased, as flow rate or metal concentrations increased, and as the exposure duration increased. Groundwater Cr and Pb were promptly attenuated by the sediments, the mobility of Cu was low and decreased rapidly as sediment pH increased above 4.5, while Cd, Ni and Zn were the most easily transported to the surface sediments and released to the overlying waters. For groundwaters of pH 3, metal migration velocities through sandy sediments were generally 0.5-2% (Cr, Pb), 1-6% (Cu) and 4-13% (Cd, Ni, Zn) of the total groundwater velocity (9-700 m/yr). The oxidative precipitation of Fe(II) and Mn(II) in the groundwaters did not affect metal mobility through the sediments. The results indicated that the efflux of acidic and metal-contaminated groundwater through estuarine sediments would affect organisms resident in sandy sediments more greatly than organisms resident in fine-grained, silty, sediments.