Water Treatment With Conventional and Alternative Coagulants: A Review

There is no access to basic sanitation for half the world's population, leading to Socioeconomic issues, such as scarcity of drinking water and the spread of diseases. In this way, it is of vital importance to develop water management technologies relevant to the target population. In addition, in the separation form of water treatment, the compound often used as a coagulant in water treatment is aluminum sulfate, which provides good results for raw water turbidity and color removal. Studies show, however, that its deposition in the human body, even Alzheimer's disease, can cause serious harm to health and disease development. The study aims to improve the coagulation/flocculation stage related to the amount of flakes, including the absence of metal sludge formed. Initial studies were concerned with assisting and comparing natural and chemical coagulants. The key chemicals used for coagulation are aluminum sulfate (alum) and poly aluminum chloride, also known as PACL and ferric chloride.

Decolourization of Congo Red Dye using Solar/H2O2 Process

The Congo red dye was decolourized by advanced oxidation process using solar/H2O2 method and the effect of various parameters on decolourization like pH, H2O2 concentration, dye concentration, solar light intensity, additives, COD and TOC removal studies and kinetic studies were investigated. The photodegradation process was done by exposing dye solutions with the concentration of 100 mg/L treated with 50% H2O2 to sunlight with the lux intensity range of 60,000-90,000 lux. The best possible pH 2 with an optimal H2O2 concentration of 1000 mM to achieve 100% decolourization within the period of 5 h. The kinetic studies done on H2O2 concentration also proved that the high solar light intensity leads to higher decolourization and low solar light intensity leads to lesser decolourization. Addition of additives like H2PO4 – and Cl– leads to a decrease in the rate of decolourization. The removal of COD and TOC removal was found to be 83.26% and 5.18%, respectively.

Removal of Arsenite and Arsenate by Indigenous Iron Ores of Pakistan

This study is focusing on the comparative study of arsenite and arsenate adsorption from the water via indigenous iron ores. The Sindh and Punjab provinces of Pakistan are badly affected by Arsenic (As) toxicity as the people are consuming arsenic contaminated groundwater. The aim of this study is to investigate the effect of anions on adsorption of arsenite As(III) and arsenate As(V). Impact of pH, contact time, adsorbent dose and shaking speed on adsorption of arsenite and arsenate is studied with the two selected iron ores from Hoshi and Shikarap from Balochistan. Hoshi and Shikarap ores exhibited higher As(III) and As (V) adsorption, respectively thus selected for further removal studies. Hoshi iron ore without sodium carbonate yields higher adsorption as compared to the samples with 100 mg/L and 1000 mg/L sodium carbonate in both As(III) and As(V). Hoshi ore exhibited the highest adsorption of 85% for As (V) without sodium phosphate dibasic and 83% for As(III). Shikarap ore for As(V) adsorbs 75% without sodium phosphate dibasic and 67% adsorption for As(III) without sodium phosphate dibasic. Shikarap ore with sodium silicate at 100 mg/L adsorbs 62% As(III) and at 1000 mg/L adsorb 52% As(III). Shikarap ore As(V) adsorption decreases from 75% without sodium silicate to 70% at 100 mg/L and even lower adsorption of 65% at a higher concentration of 1000 mg/L.

Tar Removal from Gasification/Pyrolysis by Emulsion Liquid Membrane: A Short Overview

Tar is among undesirable by-products of producer gas generated from gasification/pyrolysis of biomass. Due to the erosive and corrosive characteristics of tar, a number of tar removal studies have been done. However, considering tar availability in deficient concentration, a highly selective and energy economics method is of importance. Emulsion liquid membrane is a choice of selective and economics method. Some studies on tar removal using emulsion liquid membrane were reported. Information about definition and transport mechanism of emulsion liquid membrane was given. Effects of emulsion formulation on tar removal were described. Effects of some operating conditions in permeation process on tar removal were also presented. The study found that types and concentration of surfactant and diluent as well as emulsification methods need to be properly considered for better result. Whereas permeation speed, volume ratio, and equipment used greatly affect the emulsion breaking and tar removal efficiency. Considering low emulsion breaking, application of Taylor-Couette column as the permeation equipment for further tar removal study is proposed.