Raziya Nadeem

Organic acids pretreatment effect on Rosa bourbonia phyto-biomass for removal of Pb(II) and Cu(II) from aqueous media

The sorption of Pb(II) and Cu(II) form aqueous media by Rosa bourbonia waste phyto-biomass (RBWPB) pretreated with organic acids was investigated as a function of biosorbent dosage, initial metal ions concentration and contact time. The equilibrium biosorption data was analyzed using two kinetic models (pseudo-first order and pseudo-second order) and two isotherm models (Langmuir and Freundlich). The RBWPB was successfully applied for sequestration of both heavy metal ions; however, organic acids pretreatments decreased the metal adsorption capacity of RBWPB. The Langmuir model fitted well to the data, and the pseudo-second order kinetic equation could best describe the biosorption kinetics of Pb(II) and Cu(II) metal ions. Gibbs free energy indicated the spontaneous adsorption of Pb(II) and Cu(II) onto RBWPB.

Pb(II) biosorption from hazardous aqueous streams using Gossypium hirsutum (Cotton) waste biomass.

Studies on the biosorptive ability of Gossypium hirsutum (Cotton) waste biomass outlined that smaller size of biosorbent (0.355mm), higher biomass dose (0.20g), 5 pH and 100mg/L initial Pb(II) concentration were more suitable for enhanced Pb(II) biosorption from aqueous medium. The Langmuir isotherm model and pseudo second order kinetic model fitted well to the data of Pb(II) biosorption. Highly negative magnitude of Gibbs free energy (DeltaG degrees ) indicated that the process was spontaneous in nature. In addition to this surface coverage and distribution coefficient values of Pb(II) biosorption process were also determined. At optimized conditions Pb(II) uptake was more rapid in case of industrial effluents in comparison to synthetic solutions. FTIR spectroscopic analysis revealed that the main functional groups involved in the uptake of Pb(II) on the surface of G. hirsutum biomass were carboxyl, carbonyl, amino and alcoholic.

The use of Neem biomass for the biosorption of zinc from aqueous solutions.

An adsorbent was developed from mature leaves and stem bark of the Neem (Azadirachta indica) tree for removing zinc from water. Adsorption was carried out in a batch process with several different concentrations of zinc by varying pH. The uptake of metal was very fast initially, but gradually slowed down indicating penetration into the interior of the adsorbent particles. The data showed that optimum pH for efficient biosorption of zinc by Neem leaves and stem bark was 4 and 5, respectively. The maximum adsorption capacity showed that the Neem biomass had a mass capacity for zinc (147.08 mg Zn/g for Neem leaves and 137.67 mg Zn/g Neem bark). The experimental results were analyzed in terms of Langmuir and Freundlich isotherms. The adsorption followed pseudo-second-order kinetic model. The thermodynamic assessment of the metal ion-Neem tree biomass system indicated the feasibility and spontaneous nature of the process and DeltaG degrees values were evaluated as ranging from -26.84 to -32.75 (Neem leaves) kJ/mol and -26.04 to -29.50 (Neem bark) kJ/mol for zinc biosorption. Due to its outstanding zinc uptake capacity, the Neem tree was proved to be an excellent biomaterial for accumulating zinc from aqueous solutions.

Kinetic and Equilibrium Modeling of Pb(II) and Co(II) Sorption onto Rose Waste Biomass

Abstract An attempt was made to assess the biosorption potential of rose waste biomass for the removal of Pb(II) and Co(II) ions from synthetic effluents. Biosorption of heavy metal ions (>90%) reached equilibrium in 30 min. Maximum removal of Pb(II) and Co(II) occurred at pH 5 and 6 respectively. The biosorbent dose for efficient uptake of Pb(II) and Co(II) was 0.5 g/L for both metals. The biosorbent size affected the Pb(II) and Co(II) biosorption rate and capacity. Rose waste biomass was found effective for Pb(II) and Co(II) removal from synthetic effluents in the concentration range 10–640 mg/L. Equilibrium sorption studies showed that the extent of Pb(II) and Co(II) uptake by the rose waste biomass was better described by the Langmuir isotherm in comparison to the Freundlich model. The uptake capacities of the two metal ions were 156 and 27.15 mg/g for Pb(II) and Co(II) respectively.

Biosorption of Cu(II) ions from aqueous effluents by blackgram bran (BGB).

Biosorption of Cu(II) ions onto blackgram bran (BGB) waste biomass in a well stirred batch system was investigated and optimum conditions were determined. The maximum Cu(II) uptake capacity of BGB was 107.65 mg L(-1) at pH 5, biosorbent dose 0.025 g/100mL, biosorbent particle size <0.250 mm at an initial metal concentration of 50 mg L(-1) achieved after equilibrium time of 480 min. The equilibrium data fitted very well to Langmuir isotherm model as compared to the isothermal model of Freundlich. The pseudo 1st and 2nd order kinetic models were used to describe the kinetic data. The experimental data fitted well to 2nd order kinetic model. Due to its outstanding Cu(II) ions uptake capacity, BGB biomass proved to be an excellent material of bioorigin for accumulating Cu(II) ions from aqueous solutions.

Environmental impact assessment (EIA): an overlooked instrument for sustainable development in Pakistan

Environmental impact assessment (EIA) is a policy tool used for evaluating a project proposal from physical and socioeconomic environmental perspectives. Its aim is to reduce the impact of development on environment, hence, ensuring environmental sustainability. It is mandatory to submit an Environmental Impact Statement before starting a mega project as required by Environmental Protection Act of 1997 and Environmental Policy of Pakistan. Public consultation plays a key role in an EIA system, identifying the likely aspects and impacts of a development activity. This aspect has been ignored in effective enactment of environmental legislation in Pakistan. Sufficient legislative instruments are there to support EIA system in the country but the agencies responsible for the enforcement of environmental regulations have failed to do so. The current research gives an insight into the actual status of EIA system in Pakistan along with the feedback of EIA specialists and university teachers of the concerned departments. A new index has been devised on the basis of questionnaire response to work out the overall performance of EIA system in Pakistan or any other country. The weaknesses and deficiencies of each EIA stage have been worked out for Pakistan and elaborated with the help of the controversial Zero point Interchange Project in the capital city of Pakistan.

Immobilization of Rose Waste Biomass for Uptake of Pb(II) from Aqueous Solutions

Rosa centifolia and Rosa gruss an teplitz distillation waste biomass was immobilized using sodium alginate for Pb(II) uptake from aqueous solutions under varied experimental conditions. The maximum Pb(II) adsorption occurred at pH 5. Immobilized rose waste biomasses were modified physically and chemically to enhance Pb(II) removal. The Langmuir sorption isotherm and pseudo-second-order kinetic models fitted well to the adsorption data of Pb(II) by immobilized Rosa centifolia and Rosa gruss an teplitz. The adsorbed metal is recovered by treating immobilized biomass with different chemical reagents (H2SO4, HCl and H3PO4) and maximum Pb(II) recovered when treated with sulphuric acid (95.67%). The presence of cometals Na, Ca(II), Al(III), Cr(III), Cr(VI), and Cu(II), reduced Pb(II) adsorption on Rosa centifolia and Rosa gruss an teplitz waste biomass. It can be concluded from the results of the present study that rose waste can be effectively used for the uptake of Pb(II) from aqueous streams.

A pretreated green biosorbent based on Neem leaves biomass for the removal of lead from wastewater

ABSTRACT In the present study, Azadirachta indica (Neem) leaves biomass (a green biosorbent) was pretreated chemically and physically for possible application in the removal of lead from wastewater. Neem leaves biomass was pretreated chemically with the following chemicals HgCl2, CH3COOH, CH3CHO, and Oxalic acid and heating, autoclaving, ultrasonic bath, and boiling were used for physical pretreatment. Among all the pretreatments, boiling, acetic acid, and autoclaving pretreatments were proven to be effective at pH 5. Percentage removal of lead was 93.48% (boiling) > 91.85% (acetic acid) > 86.68% (autoclave) > 82.48% (control) and the maximum adsorption capacity (q) was 91.34 mg g−1 (boiling) > 89.75 mg g−1 (acetic acid) > 84.70 mg g−1 (autoclave) > 80.6 mg g−1 (control) after 24 h. Langmuir and Freundlich isotherms were used to represent the equilibrium relationship for different initial lead concentrations in order to understand the adsorption process. The Langmuir isotherm model was found to be useful ...

Exclusion of Zn(II) from aqueous solution using corncob (Zea mays stalk) after chemical modifications with inorganic acids and bases

AbstractIn the conducted research, corncob powder was pretreated with inorganic acids and bases. The consequence of different parameters such as initial metal concentration, pH, and contact time on Zn(II) biosorption from aqueous solution was deliberated. The order of maximum Zn(II) uptake qmax (mg g−1) for different pretreated and raw corncob powder was Ba(OH)2 (128.9) > H3PO4 (124.07) > NaOH (118.737) > H2SO4 (114.8) > HCl (93.41) > Al(OH)3 (87.9) > Native (86.74). The percentage of Zn(II) removed on corncob biomass increased with increase in pH reaching a maximum at pH 5.5. Kinetics of Zn(II) biosorption described that Zn(II) sorption rate was high in first 15–30 min and equilibrium was established after 120 min. The maximum adsorption data of native and pretreated biomass was investigated using Langmuir, Freundlich equilibrium, and Pseudo-first and second-order kinetic models. It was accomplished that structural modifications onto corncob powder lead to the formation of novel biomasses with increased ...

Utilization of immobilized distillation sludges for bioremoval of Pb(II) and Zn(II) from hazardous aqueous streams

AbstractThe present study was carried out to investigate the metal sorption potential of low-cost distillation sludges of caraway (DSC), basil (DSB), fennel (DSF), clove (DSCl), jasmine (DSJ); and immobilized distillation sludges of caraway (IDSC), basil (IDSB), fennel (IDSF), clove (IDSCl), and jasmine (IDSJ). The maximum equilibrium uptake of Pb(II) and Zn(II) ions was 0.80 and 0.30 mmol/g by IDSJ and IDSF, respectively. The optimum pH was 4.5 for Pb(II) and 6 for Zn(II). The optimum bead size was 3.5 mm. A slow decrease in Pb(II) and Zn(II) uptake was noticed with increase in shaking speed. The metal uptake capacity of Zn(II) sharply decreased with increase in temperature. Experiments revealed that sorption equilibrium reached much faster in case of textile industrial wastewater than synthetic effluents. Pseudo-first-order model fitted well to the kinetics data of Pb(II) at 30–50°C and of Zn(II) at 30–40°C. Metal uptake increased with increase in initial concentration of metal ions up to 200 mg/L. Acid...