Adsorption of lead from aqueous solution by a novel carbon based adsorbent

Lead (Pb), due to its bioaccumulation ability, has been noted to have detrimental effects on the human body affecting the metabolism, blood and kidneys (Bansal and Goyal, 2005; Bowen, 1996). It is, therefore, imperative that lead be removed from water and wastewater to protect public health and aquatic lives. Multiwall carbon nanotubes (MWCNT) were reported by Li et al. (2003) to have metal sorption capacity of 3–4 times higher than those of powder and granular activated carbon. However, membrane clogging and separation of the nanomaterials from the filtrate pose a challenge. In this work, a novel composite material consisting of carbon nanotubes (CNT) and granular activated carbon (GAC) was synthesised to solve the filtration problem in a static filter. Various percentages of nickel (1%, 3%, 5 and 7%) were used as substrate catalyst during production of the adsorbent and these were linked to the morphology and adsorption capacity of the novel material in lead adsorption. Analyses showed that increased nickel content in the substrate from 1% to 7%, during adsorbent production, resulted in a rough surface of the CNT and increased lead removal from 24% to 89%. Equilibrium concentrations of lead for the adsorbents were achieved at about 60 minutes of contact time. The novel composite material has the potential to remove toxic materials from water and bring benefit to the society

Comparing metals adsorption by carbon adsorbents: evaluating absorption properties of different carbon adsorbents

Pollution of the aquatic environment by heavy metals has detrimental effect on living species. In this work, novel carbon nano-materials (CNM) and commercial granular activated carbon (GAC) adsorbents were evaluated for removal of heavy metal matrix (Cu, Ni and Pb) from aqueous solution to meet Department of Environment (DOE) Malaysia's guideline. Results from the characterization of GAC and CNM showed that GAC had higher surface area and more functional groups. Optimum adsorption capacity of GAC and CNM were observed at pH 5 and 1 g/L dosage, while equilibrium adsorption conditions were generally noticed by 60 minutes of agitation at 100 rpm. The initial metal concentrations and functional groups on adsorbents were the major factors affecting the affinity of metals by both GAC and CNM

Growth of carbon nanomaterial on granular activated carbon

Since the discovery of carbon nanotubes (CNT) and subsequent Carbon Nanomaterials (CNMs), there has been an ever increased academic and industrial interest on there various fields of application due to their exceptional mechanical and electrical properties. In this work, granular activated carbon (GAC) made from palm Kernel shell (PKS) of mesh size 8x12 was impregnated with nickel as substrate catalyst for the growth of Carbon Nanomaterials (CNMs) in a chemical decomposition (CVD) reactor. Various percentage by weight of the nickel (1%, 3%, 5% and 7%) were impregnated on the GAC surface for CNM growth. The CNM growth took place at a fixed reaction temperature and gas flow rates for both the hydrogen gas and carbon source. Characterization of the novel composite material was carried out by using SEM, FESEM and TEM. The results show that growth was successful as at 1% nickel impregnation, while a denser network distribution and rougher surface of CNM was observed at 7% nickel. The growth of CNMs on a larger substrate GAC should make handling of the CNMs easier and it is expected to also open new doors of application in water treatment and oil refining

Metal removal from industrial wastewater by a novel carbon nanomaterial.

Recent application of nanomaterials as adsorbent for heavy metals removal has shown remarkable results which is largely due their mechanical and physical properties. In this work, feasibility of using novel carbon nanomaterials as adsorbent for the removal of copper, nickel and lead ions from an industrial wastewater by the adsorption process was investigated. The adsorbent used was a composite carbon nanomaterials (CNMs) grown on substrate granular activated carbon (GAC) made from Palm Kernel shell (PKS) of mesh size 8x12.Characterization of the adsorbent was carried out using FESEM, TEM. The effect of pH and adsorbent dosage on metals uptake from solution was investigated. The results showed successful growth of CNMs on the GAC, the adsorption of lead, copper and nickel metals ions was best at pH 5, while maximum capacity was recorded at 1 g/L dosage of adsorbent for lead and copper while nickel was at 2 g/L. The order of affinity for the metals ions by the adsorbent was Pb> Cu >Ni

Adsorption of copper, nickel and lead ions from synthetic semiconductor industrial wastewater by palm shell activated carbon

Granular activated carbon produced from palm kernel shell was used as adsorbent to remove copper, nickel and lead ions from a synthesized industrial wastewater.Laboratory experimental investigation was carried out to identify the effect of pH and contact time on adsorption of lead, copper and nickel from the mixed metals solution. Equilibrium adsorption experiments at ambient room temperature were carried out and fitted to Langmuir and Freundlich models. Results showed that pH 5 was the most suitable, while the maximum adsorbent capacity was at a dosage of 1 g/L, recording a sorption capacity of 1.337 mg/g for lead, 1.581 mg/g for copper and 0.130 mg/g for nickel. The percentage metal removal approached equilibrium within 30 min for lead, 75 min for copper and nickel, with lead recording 100 %, copper 97 % and nickel 55 % removal, having a trend of Pb2+ > Cu2+ > Ni2+ . Langmuir model had higher R2 values of 0.977, 0.817 and 0.978 for copper, nickel and lead respectively, which fitted the equilibrium adsorption process more than Freundlich model for the three metal

Surface modification of activated carbon for enhancement of heavy metals adsorption.

Carbon nanotubes were synthesized on granular activated carbon (CNT-GAC) to enhance its adsorption capacity was used as adsorbent. This work involved the characterization of the new material using FESEM, TEM and FTIR. Characterization revealed the morphology of CNT on GAC as multiwalled CNT with average outer diameter of 50 nm. Laboratory experimental investigation on the effect of pH, contact time on lead, copper and nickel adsorption from a mixed metals solution was carried out. Adsorption experiments at constant room temperature were carried out using CNT-GAC as adsorbent and fitted to Langmuir and Freundlich models. Results showed that pH 5 was the most suitable and equilibrium metal concentration was observed at 60 minutes contact time. It was noted that the sorption capacities corresponding to equilibrium varied for each metal, with lead recording 99%, copper 61% and nickel 20%, giving metal affinity trend of Pb> Cu>Ni on the CNT-GAC. Langmuir model having higher R2 value of 0.926, 0.889 and 0.986 for copper, nickel and lead adsorption was better than Freundlich in predicting the adsorption process of the three metals from the mixed metals solutio

Heavy metals removal from synthetic wastewater by a novel nano-size composite adsorbent

The effects of varying operating conditions on metals removal from aqueous solution using a novel nano-size composite adsorbent are reported in this paper. Characterization of the composite adsorbent material showed successful production of carbon nanotubes on granular activated carbon using 1 % nickel as catalyst. In the laboratory adsorption experiment, initial mixed metals concentration of 2.0 mg/L Cu2+, 1.5 mg/L Pb2+ and 0.8 mg/L Ni2+ were synthesized based on metals concentration from samples collected from a semiconductor industry effluent. The effects of operation conditions on metals removal using composite adsorbent were investigated. Experimental conditions resulting in optimal metals adsorption were observed at pH 5, 1 g/L dosage and 60 min contact time. It was noted that the percentage of metals removal at the equilibrium condition varied for each metal, with lead recording 99 %, copper 61 % and nickel 20 % , giving metal affinity trend of Pb2+ > Cu2+ > Ni2+ on the adsorbent. Langmuir’s adsorption isotherm model gave a higher R2 value of 0.93, 0.89 and 0.986 for copper, nickel and lead, respectively, over that of Freundlich model during the adsorption process of the three metals in matrix solution