Biosorption technology for removal of metallic pollutants-An overview

The main sources of metallic pollutants to the environment are the diffuse sources such as forests and agricultural soils as well as industrial and municipal wastes, which are either discharged directly or transported in to the environment. Various conventional technologies such as chemical precipitation, solvent extraction, ion exchange, membrane separation, electrochemical treatment etc. have been employed to remove metal pollutants from aqueous solution. The exploration of new technologies involves the removal of toxic metals from wastewater with the use of biological adsorption technology. The biosorption is the selective appropriate process for removal of metal ions uptake that may involve the contribution of diffusion, adsorption, chelation, complexation, coordination, or micro-precipitation mechanisms, depending on the specific substrate (biomass). In this overview, the use of the various low cost, easily available and eco-friendly biosorbents used for removal of metallic pollutants from contaminated water and their mechanism are discussed

A study on heavy metals accumulation and its uptake by Cowpea [Vigna unguiculata (L.) Walp.] fertilized with Sugar mill effluent and DAP treatment in two cropping seasons

A study was performed under natural environment to compare heavy metal accumulation in soil and Vigna unguiculata L. (Cowpea) irrigated with five rates of SME viz. 10, 25, 50, 75 and 100% concentrations and DAP treatment (applied @100Kg/ha i.e. 0.7g / per 5 Kg) and control (Bore well water) separately in both the rainy (Kharif) and summer (Zaid) seasons for 90 days. Results revealed that among various concentration of SME and DAP treatment, irrigation with 100% SME concentration significantly (P<0.001) increased Zn (323.07-341.02 %), Cu (371.23-389.04%), Ni (3666.66-4133.33%), Cd (525.00-725.00%), Cr (1444.4-1477.77%) and Fe (224.08-244.89%) in the soil. In case of V. unguiculata irrigated with different SME concentrations, maximum range of heavy metals such as Zn (2.43-2.98 mg Kg-1), Cu (2.39-2.73 mg Kg-1), Ni (0.55-0.91 mg Kg-1), Cr (1.01-1.21 mg Kg-1), Cd (0.13- 0.17 mg Kg-1), and Fe (5.54-6.18) were observed at 100% concentration of SME than that of DAP treatment in both the cultivated seasons. However, the concentration of all the metals Zn, Cu, Ni, Cd, Cr and Fe in soil and plant were lower than toxicity threshold i.e. within the permissible limit. Enrichment factor (Ef) for soil/V. unguiculata was recorded maximum with Ni (37.66-42.33) / (24-30.33) and minimum with Fe (3.24-3.44) / (2.28-2.52) after 90 days of SME irrigation than DAP in both the cropping seasons of Kharif and Zaid. The minimum accumulation of Fe in both soil and crop showed that metals with completely filled d orbitals (d8, Fe) were least incorporated into the V. unguiculata crop

Efficiency of aluminum and iron electrodes in removal of colour, turbidity and total suspended solid from biologically treated municipal wastewater

The present investigation was undertaken to observe the effect of different combinations of aluminium and iron (Al-Al, Al-Fe, Fe-Fe and Fe-Al) electrodes on the removal of colour, turbidity (TD) and total suspended solids (TSS) of biologically treated municipal wastewater ( BTMW) using applied potential (V), operating time (OT) and initial pH. The maximum removal of colour (98.7 %) and TSS (96.89 %) was found with the use of Al-Al combination with optimum operating conditions (Voltage: 40 V; OT: 40 mins.; IED: 1.0 cm; EA: 160 cm2; initial pH: 7.5 and ST: 30 mins). It was interesting to note that TD of BTMW was completely removed at these optimal operating conditions. The economic evaluation of electrode combinations was observed to be in the order of Fe-Al (1.17 US /m3)> Al-Fe (1.11 US /m3)> Fe-Fe (1.08 US /m3) >Al-Al (1.01 US /m3) in terms of energy and electrode consumption. Thus, the BTMW can be effectively treated with the Al-Al electrode combination in comparison to other electrode combinations (Al-Fe , Fe-Fe and Fe-Al)

A review on sewage sludge (Biosolids) a resource for sustainable agriculture

Sewage sludge (Biosolids) generation is fastly increasing resulting from the regular increase of population, urban planning and industrial developments worldwide. The sludge needs to be adequately treated and environmentally managed to reduce the negative impacts of its application or disposal. The present review deals with the different applications of sewage sludge for sustainable agriculture. The scattered literature is harnessed to critically review the uses of biosolids to promote sustainable practices focusing on the productive uses of sewage sludge or biosolids. Biosolids or sewage sludge is the byproduct of municipal wastewater, sewage effluent and effluent treatment plants. The treatment plants are generating huge amount of biosolids. The present review focuses on the different applications of biosolids or sewage sludge as in many countries the biosolids or sewage sludge are frequently using for various purposes like for biogas production, land filling, organic fertilizer, soil amendment, and to enhance the crop yield of agricultural crops. Therefore, biosolids or sewage sludge is in the consideration as a resource worldwide. Besides this higher content of different heavy metals and microorganisms are the important constraints for the application of biosolids or sewage sludge in the various fields. Thus, this review emphasizes the different applications and possible limitations for the use of biosolids or sewage sludge as a resource. Efforts have been made on the possible pretreatment of biosolids or sewage sludge to make it more feasible for their applications. Therefore, different properties of biosolids or sewage sludge, their applications along with possible limitations have been discussed in the present review to formulate the biosolids or sewage sludge as a resource for the sustainable development

Studies on Thin Films of Antimony Vacuum Evaporated from a Knudsen-Type Source

A Knudsen-type evaporation source was used for the deposition of thin films of antimony to study their growth and microstructure under different rates of evaporation and substrate temperatures when vacuum evaporated onto air-cleaved KC1, mica, amorphous carbon and doped KCl substrates. The crystallisation of these films on exposure to an electron beam of moderate intensity inside the electron microscope was studied, and the orientations of the crystallised films wrt the substrate were established. It has been concluded that antimony films prepared by this source compare well with those prepared by other sources of vacuum evaporation

Contamination of Asian herbal drugs : Need for its critical evaluation

Herbal drugs have been used as remedies for the treatment of large number of humans, ailments since ancient times as the traditional medicine system; India has a glorious past, having first documented record of fully developed medical science known as Ayurveda written by several ancient Rishi’s. Major groups of indigenous system of medicine are based on herbal drugs. A survey made by WHO indicated that about 80% of the world population relies on herbal drugs. Herbal drugs are becoming more popularized and important even in the developednations with hope of their non-toxicity and may play a role of substitute to overcome the problems of multi drug resistant pathogens. Cultivation of drug plants has been started in large scale without considering the land quality and in certain cases irrigation with waste water. Application of different fungicides, pesticides in that specific field or in neighboring fields may be directly deposited superficially or may be absorbed by the plant system. Therefore in the present situation possibilities of the Asian herbal drugs, contaminated with large number of toxic components cannot be ignored which may severely hurt human life in place of healing or curing.These contaminants may be either alone or in combination and may be originated intrinsically, extrinsically and deliberately. Certain contaminants may be highly toxic and may cause severe adverse effect in the human system. Some of the important contaminants are the heavy metals like lead, arsenic, cadmium, mercury, copper and pesticides. Adulteration of modern drugs to enhance drug potency and heterogenous microbial population including human pathogens may contaminate both raw and powdered herbal drugs. Among these contaminants, microbial contamination seems more severe and may be due to their dual action on the drug i.e. utilization of medicinally important chemical components as nutrients and in certain cases by producing certain mycotoxins, which may be even carcinogenic under certain conditions . Critical evaluation of both raw and powdered herbal drugs for contaminants is the urgent need of the time in order to provide safety measures in herbal health care medicine

Effects of integrated nutrient management on agronomical attributes of tomato (Lycopersicon esculentum L.) under field conditions

In this investigation the effects of different integrated nutrient management on agronomical attrib-utes of tomato (Lycopersicon esculentum L. cv. F1 Hybrid Arka Rakshak) under field conditions were investigated. Ten nutrients treatments viz., without nutrient (control) (T1), recommended dose of fertilizer (RDF) (T2), agro residue vermicompost (ARV) @ 5 t ha-1 (T3), sugarcane pressmud compost (SPC) @ 5 t ha-1 (T4), cattle dung compost (CDC) @ 12.5 t ha-1 (T5), sewage sludge (SS) @ 2 t ha-1 (T6), T7 (50 % RDF + ARV @ 5 t ha-1), T8 (50 % RDF + SPC @ 5 t ha-1), T9 (50 % RDF + CDC @ 12.5 t ha-1) and T10 (50% RDF + SS @ 2 t ha-1) were used for the cultivation of L. esculentum. The results showed that different treatments showed significant (P-0.05/P-0.01) change in EC, OC, TKN, PO43-, Na+, K+, Ca2+, Mg2+, Cd, Cr, Cu, Fe, Mn and Zn of the soil. Among various treatments the most plant height, root length, dry weight, chlorophyll content, LAI, number of flowers/plant, fruits/plant, crop yield/plant, and biochemical ingredient like crude protein, dietary fiber, total carbohydrates and total sugar of L. esculentum was recorded with 50% RDF + ARV @ 5 t ha-1. The agronomical performance of L. esculentum was recorded in the order of T7 > T10 > T9 > T8 > T3 > T6 > T5 > T4 > T2 > T1 treatments. Thus, sole ARV and 50% RDF along with ARV @ 5 t ha-1 can be used to achieve the maximum crop yield of L. esculentum

Toxicity of Vernonia anthelmintica Linn. (Asteracea) seeds against mosquitoes vectors

The Toxicological activity (larvicidal, adulticidal and repellent toxicity) of Vernonia anthelmintica seeds fraction was tested against different species of mosquito vectors viz, malaria (Anopheles culicifacies and Anopheles stephensi), filaria (Culex quinquefasciatus) and dengue (Aedes aegypti). The larvicidal toxicity of Vernonia anthelmintica seeds fraction was evaluated against the early 4th instars larvae of different mosquitoes species. Mean LC50 value of the column fraction KAL-4 from seeds of V. anthelmintica against the larvae of An. culicifacies, An. stephensi, Culex quinquifaciatus and Aedes aegpyti were found to be 64 ppm, 70 ppm, 143 ppm and 166 ppm respectively. The larvicidal toxicity was more against An. culicifacies, An. stephensi than Culex quinquifaciatus and Aedes aegypti. The seed extracts did not show any adulticidal toxicity and repellent toxicity even at 10% concentrated impregnated paper and 5% on human hand, respectively

A review on scientific technologies in practice to innovate plant based molecules and to improve herbal drug quality to overcome health problems

Medicines obtained from drug plants and other sources are commonly called traditional medicines. They have played an important role in the treatment of several human diseases since ancient times. India possessed a great wealth of traditional health care system known as Ayurveda related to the use of plant species. The global market of herbal drugs has a great potential around the world. Demand of plant based medicines is also increasing among western countries because of a general consideration that most allopathic drugs are associated with more or less side effects. Many pharmaceutical companies are now manufacturing Ayurvedic phytopharmaceutical products. However, enough efforts have not been made to get suitable substitute of modern allopathic medicines from these traditionally used drug plants and herbal drugs. This traditional system of healthcare in India still needs extensive evidence-based scientific researches in promoting its therapies. This review paper deals with modern scientific approaches to find out new plant based molecules and to develop new technologies in a continuous process and should be applied in the practice to improve the quality of herbal drugs in Indian pharmaceutical industries. Critical assessment of quality assurance including researches on pharmacognosy, chemistry, pharmacology, antimicrobial activity and clinical studies carried out on various Ayurvedic medicinal plants are also being presented

Phyto-adsorption treatment of paper mill effluent using leaf powder of water hyacinth (Eichhornia crassipes [Mart.] Solms

In this present study, an experiment was performed to find the potential of leaf powder of water hyacinth (Eichhornia crassipes) in treating paper mill effluent. During the study the value of different parameters viz., pH (5.80±0.10), TDS (980.22±12.52 mgL-1), EC (6.52±0.11 dS m-1), BOD (86.42±4.61 mgL-1), COD (281.01±8.66 mgL-1), PO43- (71.46±6.00 mgL-1), TKN (84.99±3.92 mgL-1), Na (136.94±6.66 mgL-1), K (95.01±3.48 mgL-1) and total hardness (442.39±3.78 mgL-1) of paper mill effluent were recorded higher before bio-adsorption treatment using leaf powder of E. crassipes. The leaf powder of E. crassipes significantly (P<0.05/P<0.01) removed TDS, EC, BOD, COD, TKN, Na, K and total hardness of the paper mill effluent. The result of the present study on the  bio-adsorption treatment using leaf powder of E. crassipes of paper mill effluent showed maximum reduction in the effluent characteristics viz., pH (6.62±0.08), TDS (848.42±7.67 mgL-1), EC (4.08±0.17 dS m-1), BOD (62.56±3.39 mgL-1), COD (218.11±8.59 mgL-1), PO43- (50.13±4.33 mgL-1), TKN (63.04±6.47 mgL-1), Na (100.06±6.99 mgL-1), K (66.00±7.38 mgL-1) and total hardness (347±9.86 mgL-1) of paper mill effluent after bio-adsorption treatment using leaf powder of E. crassipes. The maximum removal of TDS (13.45%), EC (37.43%), BOD (25.89%), COD (22.38%), PO43- (29.85%), TKN (25.83%), Na (26.94%), K (30.54%) and Total hardness (21.56%) in the paper mill effluent were recovered after phyto-adsorption treatment using leaf powder of E. crassipes. The decrease of paper mill effluent parameter is likely due to that the leaf powder of water hyacinth absorbs the nutrient from the effluent. Therefore, the leaf powder of can be used as phyto-adsorbent for the removal of various pollution parameters