Hesam Kamyab

Comprehensive review on phytotechnology: Heavy metals removal by diverse aquatic plants species from wastewater

Environmental pollution specifically water pollution is alarming both in the developed and developing countries. Heavy metal contamination of water resources is a critical issue which adversely affects humans, plants and animals. Phytoremediation is a cost-effective remediation technology which able to treat heavy metal polluted sites. This environmental friendly method has been successfully implemented in constructed wetland (CWs) which is able to restore the aquatic biosystem naturally. Nowadays, many aquatic plant species are being investigated to determine their potential and effectiveness for phytoremediation application, especially high growth rate plants i.e. macrophytes. Based on the findings, phytofiltration (rhizofiltration) is the sole method which defined as heavy metals removal from water by aquatic plants. Due to specific morphology and higher growth rate, free-floating plants were more efficient to uptake heavy metals in comparison with submerged and emergent plants. In this review, the potential of wide range of aquatic plant species with main focus on four well known species (hyper-accumulators): Pistia stratiotes, Eicchornia spp., Lemna spp. and Salvinia spp. was investigated. Moreover, we discussed about the history, methods and future prospects in phytoremediation of heavy metals by aquatic plants comprehensively.

Lipid production by microalgae Chlorella pyrenoidosa cultivated in palm oil mill effluent (POME) using hybrid photo bioreactor (HPBR)

Palm oil mill effluent (POME) as high organic wastewater is a promising substrate in the scenario of algae bloom, by enhancing its lipid production to be further used in biofuel manufacturing. In this research, effect of POME as high nutritional substrate, different cultivation scales such as flask or hybrid photo bioreactor (HPBR), carbon-to-total nitrogen (C:TN) ratio, various light and dark cycles, and diverse organic loading rates (OLR) on the lipid productivity of microalgae Chlorella pyrenoidosa was assessed. Results demonstrated high microalgae growth rate (1.80 d �1 ) at 250 mg COD/L of substrate, while moderate increase (1.37 d �1 ) and growth inhibition (0.80 d �1 ) were recorded at 500 mg COD/L and 1,000 mg COD/L of substrate concentration, respectively. Furthermore, a result proved that low-volume cultivation of microalgae in a flask with lipid productivity at 1.78 mg/L d significantly restricted microalgae production compared with larger scale such as HPBR with lipid productivity at 230 mg/L d. Moreover, highest lipid production at 44.5, 114.9, and 100.5 mg/L d, C:TN ratio at 100:6 and OLR at 36 kg COD/m 3 d, respectively, were documented for continuous illuminaion (24 h). The combination of above conditions can be optimal setting to reach the highest lipid productivity by microalgae C. pyrenoidosa. In addition, the results of this study can be further considered in microalgae lipid production using other wastewaters in order to enhance the lipid production as well as wastewater treating functions.

Application of Proteus mirabilis and Proteus vulgaris mixture to design self-healing concrete

AbstractThis study investigated two indigenous micro-organisms that can be isolated from soil. The isolated micro-organisms could precipitate calcium carbonate. These micro-organisms were applied to design self-healing concretes. Concrete is one of the most important materials which is used to build structures. Strength and durability of concrete is very important. Hence, a lot of research in this field is being conducted. Although a few reports can be found on the use of different micro-organism to design self-healing concretes, no research has been carried out to isolate suitable indigenous micro-organisms in Malaysia. In this study two strains of microorganisms were isolated from soil. Broken concrete was treated by a medium culture (MC) containing micro-organisms. Results of this study showed that, cracked concrete could be filled by calcium carbonate after treating by a MC containing micro-organisms. However, this treatment is not very effective on the strength of concrete. Results of this study can ...

The efficient role of aquatic plant (water hyacinth) in treating domestic wastewater in continuous system

ABSTRACT In this study, water hyacinth (Eichhornia crassipes) was used to treat domestic wastewater. Ten organic and inorganic parameters were monitored in three weeks for water purification. The six chemical, biological and physical parameters included Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Ammoniacal Nitrogen (NH3-N), Total Suspended Solids (TSS), and pH were compared with the Interim National Water Quality Standards, Malaysia River classification (INWQS) and Water Quality Index (WQI). Between 38% to 96% of reduction was observed and water quality has been improved from class III and IV to class II. Analyses for Electricity Conductivity (EC), Salinity, Total Dissolved Solids (TDS) and Ammonium (NH4) were also investigated. In all parameters, removal efficiency was in range of 13–17th day (optimum 14th day) which was higher than 3 weeks except DO. It reveals the optimum growth rate of water hyacinth has great effect on waste water purification efficiency in continuous system and nutrient removal was successfully achieved.

Review of microalgae growth in palm oil mill effluent for lipid production

Wastewater treatment using microalgae is an eco-friendly process without secondary pollution. During the process, the wastewater produced is reused, which allows efficient nutrient recycling. This review provides constructive information to enable progress of competent technology for microalgae based productions in palm oil mill effluent (POME). The characteristics of POME that will be described in this paper would be a source of pollution in water if discharged directly. Since microalgae have great potential to be isolated and cultivated in POME, previous studies to improve POME based culture media are still limited. Microalgae are highly competent in diminishing CO2 emissions and reducing the organic components in POME. In conclusion, biological treatments by using microalgae discussed in this paper and the lipid production from microalgae biomass can be used as an alternative for energy production. The POME treatment with microalgae may meet the standards or limits before being discharged into the water body.

Microplastics pollution in different aquatic environments and biota: A review of recent studies

Microplastics (MPs) are generated from plastic and have negative impact to our environment due to high level of fragmentation. They can be originated from various sources in different forms such as fragment, fiber, foam and so on. For detection of MPs, many techniques have been developed with different functions such as microscopic observation, density separation, Raman and FTIR analysis. Besides, due to ingestion of MPs by wide range of marine species, research on the effect of this pollution on biota as well as human is vital. Therefore, we comprehensively reviewed the occurrence and distribution of MPs pollution in both marine and freshwater environments, including rivers, lakes and wastewater treatment plants (WWTPs). For future studies, we propose the development of new techniques for sampling MPs in aquatic environments and biota and recommend more research regarding MPs release by WWTPs.

An Analytical Approach to Calculate the Charge Density of Biofunctionalized Graphene Layer Enhanced by Artificial Neural Networks

Graphene, a purely two-dimensional sheet of carbon atoms, as an attractive substrate for plasmonic nanoparticles is considered because of its transparency and atomically thin nature. Additionally, its large surface area and high conductivity make this novel material an exceptional surface for studying adsorbents of diverse organic macromolecules. Although there are plenty of experimental studies in this field, the lack of analytical model is felt deeply. Comprehensive study is done to provide more information on understanding of the interaction between graphene and DNA bases. The electrostatic variations occurring upon DNA hybridization on the surface of a graphene-based field-effect DNA biosensor is modeled theoretically and analytically. To start with modeling, a liquid field effect transistor (LGFET) structure is employed as a platform, and graphene charge density variations in the framework of linear Poisson– Boltzmann theories are studied under the impact induced by the adsorption of different values of DNA concentration on its surface. At last, the artificial neural network is used for improving the curve fitting by adjusting the parameters of the proposed analytical model.

Cost-Benefit and Greenhouse-Gases Mitigation of Food Waste Composting: A Case Study in Malaysia

Waste generation nowadays is rising in the world and it seems hard to prevent it. Municipal Solid Waste (MSW) has been a major problem worldwide, especially in the fast growing cities and towns in the developing countries. This study aims to estimate the cost benefit and mitigation of greenhouse gases (GHGs) by converting the on-campus food and green waste generated in Universiti Teknologi of Malaysia (UTM) campus to compost. This study calculated the costing which includes the transportation, operating and equipment costs if green and food waste were converted into compost. The analyses were made with the basis of the pilot scale operation in Phase I operation. Extrapolation was made to project the further four phases of composting with higher amount of waste to estimate the potential profit. The results obtained from this study indicated that composting has the potential to generate a significant profit of Malaysia Ringgit (MYR)1.6 M/y based on 2,700 t/y of food and green waste composted. At the same time, the total solid waste supposedly to be sent to the landfill can be reduced by at least 47 %. Moreover, this study revealed that the composting process is able to reduce the GHGs emission rate by 90 %, i.e. the GHGs produced by the composting process is shown to be only 10 % of the total GHGs produced by landfill dumping given the same amount of solid waste to be disposed at the landfill site.

Magnetic Nano-Сomposites and their Industrial Applications

Magnetic nanocomposites are multi-component, nanosized magnetic materials, to generate the response to an external stimulus (i.e., outer inert or alternative magnetic field). The novel nanocomposites is a combination of excess of various materials such as liquid crystals, silica, gels, renewable polymers, carbon along with different magnetic particles. They have immense applications in the field of medical diagnosis and therapy, catalysis and separation. These nanocarriers are mainly classified into nanotubes, nanosheets, spherical nanoparticles, nanofibres, highly porous nanocomposites. The porous nanostructures provides a better surface for the entrapment or covalent binding of enzymes, proteins, biomolecules and drugs but the major challenge is to design and synthesize a desired structure with suitable surface properties and biocompatibility. Extensive attempts have been made to manipulate the mesoporous materials and its combination with other structure in order to synthesize a matrix with appropriate pore size, large surface area to volume ratio. “Bottom-up” and “Bottom-down” chemical-based synthesis methods have been widely employed to prepare magnetic nanoparticles. Magnetic nanocomposites are synthesized from magnetic nanoparticles and biopolymers by using sol-gel technique, chemical precipitation methods and NanogenTM, a microwave plasma method. In this chapter, we described the advances and developments in the formation/synthesis of magnetic nanocomposites. This chapter will review the characteristics, properties and applications of the magnetic nanocomposites.

Bioconcrete Strength, Durability, Permeability, Recycling and Effects on Human Health: A Review

Concrete has become as one of the common material in the construction sector, which makes it of great interest to the researchers in pursuit for the production of concrete with better properties. This is mainly because the existing concrete has several limitations in terms of strength, ductility, durability and resistance to cracking. To overcome this problem with the use of bioconcrete, it can self-heal and also posses other value added features like high durability, increased strength and less water absorption capacity. Even though several studies to date have been focused on the development of bioconcrete but the aspects of advantage and disadvantages using bioconcrete has not been discussed so far. The objective of this study is to review the positive and negative impacts of bioconcrete application in the aspect of strength, durability, permeability, recycling and its effects on human health. A systematic review has been used to review some of the relevant and recently published works in this area. The diverse advantages has been mainly covered like; increasing the concrete durability, increasing the concrete strength, increasing of concrete permeability, and ability of biological concrete for recycling. The effect of biological concrete on human health as one of the main disadvantages using bioconcrete has also been covered. The findings of this paper can be considered significant for the stakeholders in the construction sector, as well as the engineers in gaining insight towards the potential use of biological concrete in the field of construction, considering both the merits and demerits of using biological concrete. As a conclusion, the research paper highlights several advantages and disadvantages of bioconcrete that helps to predict the future commercial application of bioconcrete in the construction industry.