Water hyacinth as a biosorbent: A review

Water hyacinth (Eichhornia crassipes), has attracted significant attention as the world’s worst invasive aquatic plant due to its extremely rapid proliferation and congest growth, presenting serious challenges in navigation, irrigation, and power generation. Attempts to control the weed have proved to be costly with minimum results. However, the same plant has demonstrated an amazing ability to absorb and concentrate many toxic metals from aquatic environments. Consequently, research activity on utilization of the plant has been registered over the last few decades. This article reviews literature related to the utilization of E. crassipes in the biosorption and recovery of metals from aquatic environments. Availability in large quantities, high biosorption capacity, renewability and low cost determine the extent to which biosorbents can be adapted technologically. Sorption dynamics through classical and competitive models, effect of physical and chemical treatment, pH, temperature, initial metal concentration and biosorbent dose on metal removal by water hyacinth is discussed.Keywords: Biosorption, heavy metals, precious metals, recovery, water hyacinth

A comparative study of the performance of the Chitungwiza, Marondera and Crowborough sewage treatment plants in Zimbabwe

A comparative study on the performance of effluent treatment plants in Zimbabwe's urban settlements.The performance of the Chitungwiza, Marondera and Crowborough Sewage treatment plants in Zimbabwe were evaluated by monitoring the levels of suspended solids (SS), dissolved solids (DS), dissolved oxygen (DO), biological oxygen demand (BOD), K+, Na+, Ca2+, Mg2+, CI-, S042-, N03‘, N02‘, and P043- ions in the period May 1994 to September 1995. The performance of the three plants were assessed by comparison to the UK conventional effluent 30:20 standard for SS, BOD, Cl', N03‘ and P043* ions. All three plants conformed to this standard for nitrate ion, while for Chitungwiza and Marondera plants the levels of BOD, SS, chloride and phosphate ions were in excess of the Standard. In addition, the Chitungwiza sewage plant effluent contained very high levels of nitrite ion

Divalent metal ion removal from aqueous solution by acid-treated and garlic-treated Canna indica roots

The biosorption of different metal ions (Cu2+, Zn2+, Ni2+, Pb2+ and Co2+) by dried roots of Canna indica biomass was investigated using a batch sorption technique. The equilibrium retention capacities of the metal ions determined from the Langmuir isotherm showed that C. indica had the largest sorption capacity for Pb2+ ions and the least sorption for Ni2+. The results also showed that garlic-treatment of C. indica biomass enhanced its sorption capacity for the divalent metal ions, with the enhancement factor varying from 1.22 to 1.44. The biosorption process was found to be exothermic for all metal ions studied (\u394H values varying from -4.438 to -12.716 kJ mol-1), with physisorption being the most likely mechanism of uptake. In conclusion, studies on biosorption of heavy metals by C. indica are important because they may contribute in aiding the innovative removal of metal ions from contaminated industrial effluents

Agro-morphological Characterization of West and Central African Pearl Millet Accessions

Pearl millet [Pennisetum glaucum (L.) R. Br.] was domesticated in Sahelian West Africa. This highly outcrossing crop is one of the most important staple cereals in the semiarid tropics, adapted to very harsh rain-fed conditions. Agro-morphological characterization of local germplasm is very important to better understand existing diversity, ease targeted genetic broadening of breeding populations, and potentially link this knowledge to genotypic information. The objectives of our study were to (i) characterize West and Central African (WCA) pearl millet accessions based on their agro-morphological traits; (ii) evaluate the possibility to group accessions based on their agro-morphological characteristics; (iii) determine geographic patterns of phenotypic differentiation; and (iv) derive conclusions for pearl millet improvement in WCA. A total of 360 early-tomedium maturity accessions were phenotyped for 12 agro-morphological traits at six environments in WCA. Wide ranges of all observed traits indicated a high diversity of the tested accessions. Principal component analysis revealed very large diversity within individual countries, especially within Mali and Burkina Faso. Some limited grouping of accessions from Niger, Senegal, Cameroon, Morocco, and Mauritania was observed for individual principal component axes. Geographical differentiation and country differences were detected for several traits. The results and data presented in our study reflect WCA pearl millets’ tremendous diversity and adaptability to a wide range of environments and give a sound basis for breeders to select and utilize this germplasm to serve the manifold needs of WCA pearl millet farmers

Pre-concentration of trace metals by ICP-AES using chemically-treated and untreated hyacinth weed, Eichhornia Crassipes

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Pre-concentration of trace metals by ICP-AES using chemically-treated and untreated hyacinth weed, Eichhornia Crassipes

Due to technical difficulties, the full text of this article is currently unavailable. We are working to fix this and apologize for any inconvenience

Divalent metal ion removal from aqueous solution by acid-treated and garlic-treated Canna indica roots

The biosorption of different metal ions (Cu2+, Zn2+, Ni2+, Pb2+ and Co2+) by dried roots of Canna indica biomass was investigated using a batch sorption technique. The equilibrium retention capacities of the metal ions determined from the Langmuir isotherm showed that C. indica had the largest sorption capacity for Pb2+ ions and the least sorption for Ni2+. The results also showed that garlic-treatment of C. indica biomass enhanced its sorption capacity for the divalent metal ions, with the enhancement factor varying from 1.22 to 1.44. The biosorption process was found to be exothermic for all metal ions studied (ΔH values varying from -4.438 to -12.716 kJ mol-1), with physisorption being the most likely mechanism of uptake. In conclusion, studies on biosorption of heavy metals by C. indica are important because they may contribute in aiding the innovative removal of metal ions from contaminated industrial effluents